1850 1% sample

• 1-in-100 national random sample of the free population.
• African-American slaves are not included in this dataset. Individual-level data on the 1850 slave population is available at the 1850-60 Slave PUMS website.
• Approximately 38,000 household and 198,000 person records.

1860 1% sample

• 1-in-100 national random sample of the free population.
• African-American slaves are not included in this dataset. Individual-level data on the 1860 slave population is available at the 1850-60 Slave PUMS website.
• Approximately 54,100 household and 274,000 person records.

1860 1% sample with black oversample

• 1-in-100 national random sample of the free population with a 1-in-50 over-sample of the free African-American population.
• African-American slaves are not included in this dataset. Individual-level data on the 1860 slave population is available at the 1850-60 Slave PUMS website.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Approximately 57,000 household and 283,000 person records.

1870 1% sample

• 1-in-100 national random sample of the population.
• Approximately 80,000 household and 380,000 person records.

1870 1% sample with black oversample

• 1-in-100 national random sample of the population with a 1-in-50 over-sample of the African-American population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Approximately 92,000 household and 445,000 person records.

1880 1% sample

• 1-in-100 national random sample of the population.
• Approximately 107,000 household and 503,000 person records.

1880 Preliminary 5% sample with oversamples

• 1-in-20 national random sample of households not including a minority.
• 1-in-10 national random sample of households including a minority.
• "Minorities" are defined as persons whose race was Native American or African-American, whose race or birthplace indicated that they were Chinese, or whose name or birthplace indicated Hispanic origins.
• The Preliminary sample includes data only from odd-numbered microfilm reels (e.g., 1, 3, 5, 7). Each reel generally contains census manuscripts for several counties, with counties organized alphabetically by state. For this reason, counties on even-numbered reels are not represented in this dataset. All counties will be represented in the final 10% 1880 sample.
• This is a weighted sample. Weights must be used to produce accurate estimates.
• Approximately 620,000 household and 2,949,000 person records.

1900 1% sample

• 1-in-100 national random sample of the population, including Alaskans, Hawaiians, and American Indians.
• Note the 1900-1920 samples include data from Alaska and Hawaii, even though they were not states until 1959. The 1930-1950 samples do not include data from Alaska and Hawaii.
• Aproximately 175,000 houshold and 760,000 person records.

1900 1% sample with oversamples

• 1-in-100 national random sample of the population, with 20% oversamples of Alaskans, Hawaiians, and persons enumerated on the American Indian schedules.
• Note the 1900-1920 samples include data from Alaska and Hawaii, even though they were not states until 1959. The 1930-1950 samples do not include data from Alaska and Hawaii.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Approximately 199,000 household and 845,000 person records.

1900 "Preston" sample

• 1-in-760 national random sample of the population.
• Approximately 27,000 household and 100,000 person records.
• This sample is no longer available via the IPUMS extract system. It is only available via the IPUMS downloads page.

1910 1% sample

• 1-in-100 national random sample of the population, including Alaskans, Hawaiians, and persons enumerated on the American Indians schedules.
• Note the 1900-1920 samples include data from Alaska and Hawaii, even though they were not states until 1959. The 1930-1950 samples do not include data from Alaska and Hawaii.
• Approximately 218,000 household and 923,000 person records.

1910 1.4% sample with oversamples

• 1-in-70 national random sample of the population, with large oversamples of Hispanics, Blacks, Alaskans, Hawaiians, and persons enumerated on the American Indian schedules.
• Note the 1900-1920 samples include data from Alaska and Hawaii, even though they were not states until 1959. The 1930-1950 samples do not include data from Alaska and Hawaii.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Approximately 362,000 household and 1,503,000 person records.

1910 Puerto Rico Sample

• There are three combined samples in the 1910 Puerto Rican sample: a 1-in-10 sample; an over-sample of households in the municipality of Loiza (an African-descent enclave); and an over-sample of households located in coffee regions.
• This sample was originally made at the University of Wisconsin-Madison by Alberto Palloni, Halliman W. Winsborough, and Francsico Scarano. Some codes and values in the IPUMS sample differ from those in the original UW sample (which is available from ICPSR).
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Approximately 29,000 household and 137,900 person records.

1920 1% sample

• 1-in-100 national random sample of the population.
• Note the 1900-1920 samples include data from Alaska and Hawaii, even though they were not states until 1959. The 1930-1950 samples do not include data from Alaska and Hawaii.
• Approximately 260,000 household and 1,050,000 person records.

1920 Puerto Rico Sample

• There are three combined samples in the 1920 Puerto Rican sample: a 1-in-10 sample; an over-sample of households in the municipality of Loiza (an African-descent enclave); and an over-sample of households located in coffee regions.
• This sample was originally made at the University of Wisconsin-Madison by Alberto Palloni, Halliman W. Winsborough, and Francsico Scarano. Some codes and values in the IPUMS sample differ from those in the original UW sample (which is available from ICPSR).
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Approximately 32,000 household and 160,500 person records.

1930 1% sample

• 1-in-100 national random sample of the population.
• Note that the 1930-1950 samples do NOT include data from Alaska and Hawaii. Samples from 1900-1920 and 1960-present include data from Alaska and Hawaii.
• Approximately 315,000 household and 1,216,000 person records.

1940 1% sample

• 1-in-100 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Note that the 1930-1950 samples do NOT include data from Alaska and Hawaii. Samples from 1900-1920 and 1960-present include data from Alaska and Hawaii.
• Every household has one "sample-line" person who answered additional census questions.
• Only places of at least 100,000 population can be identified with any geographic variable.
• Approximately 391,000 household and 1,350,000 person records.

1950 1% sample

• 1-in-100 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• Note that the 1930-1950 samples do NOT include data from Alaska and Hawaii. Samples from 1900-1920 and 1960-present include data from Alaska and Hawaii.
• Every household has one "sample-line" person who answered additional census questions.
• Only places of at least 100,000 population can be identified with any geographic variable.
• Approximately 461,000 household and 1,922,000 person records.

1960 1% sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic unit is state.
• Approximately 579,000 household and 1,780,000 person records.

1970 1% Form 1 State sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic unit is state.
• This sample was originally called the "5% state sample" because Form 1 was given to 5% of the population.
• 1970 Form 1 samples contain a somewhat different set of variables than Form 2 samples.
• Approximately 744,000 household and 2,030,000 person records.

1970 1% Form 2 State sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic unit is state.
• This sample was originally called the "15% state sample" because Form 2 was given to 15% of the population.
• 1970 Form 2 samples contain a somewhat different set of variables than Form 1 samples.
• Approximately 744,000 household and 2,030,000 person records.

1970 1% Form 1 Metro sample

• 1-in-100 national random sample of the population. (Note, this is not a sample only of metro areas.)
• The smallest identifiable geographic units are metropolitan areas and county groups: combinations of counties totaling at least 250,000 population. State of residence is unknown for county groups that straddle state boundaries.
• This sample was originally called the "5% county group sample" because Form 1 was given to 5% of the population.
• 1970 Form 1 samples contain a somewhat different set of variables than Form 2 samples.
• Approximately 744,000 household and 2,030,000 person records.

1970 1% Form 2 Metro sample

• 1-in-100 national random sample of the population. (Note, this is not a sample only of metro areas.)
• The smallest identifiable geographic units are metropolitan areas and county groups: combinations of counties totaling at least 250,000 population. State of residence is unknown for county groups that straddle state boundaries.
• This sample was originally called the "15% county group sample" because Form 2 was given to 15% of the population.
• 1970 Form 2 samples contain a somewhat different set of variables than Form 1 samples.
• Approximately 744,000 household and 2,030,000 person records.

1970 1% Form 1 Neighborhood sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic units are "neighborhoods" of about 4000 population (approximately the size of census tracts). The precise location of a given neighborhood is suppressed; only its census region/division is provided. Households from 42,950 separate neighborhoods are included in the sample. Both the Form 1 and Form 2 neighborhood samples contain cases from each of the 42,950 neighborhoods (about 17 households per neighborhood from each sample).
• Neighborhood samples contain a set of additional variables giving summary statistics for the neighborhood in 1970 (e.g., percent of population age 65 or older). The extra variables are appended onto the end of the household record.
• This sample was originally called the "5% neighborhood sample" because Form 1 was given to 5% of the population.
• 1970 Form 1 samples contain a somewhat different set of variables than Form 2 samples.
• Approximately 744,000 household and 2,030,000 person records.

1970 1% Form 2 Neighborhood sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic units are "neighborhoods" of about 4000 population (approximately the size of census tracts). The precise location of a given neighborhood is supressed; only its census region/division is provided. Households from 42,950 separate neighborhoods are included in the sample. Both the Form 1 and Form 2 neighborhood samples contain cases from each of the 42,950 neighborhoods (about 17 households per neighborhood from each sample).
• Neighborhood samples contain a set of additional variables giving summary statistics for the neighborhood in 1970 (e.g., percent of population age 65 or older). The extra variables are appended onto the end of the household record.
• This sample was originally called the "15% neighborhood sample" because Form 2 was given to 15% of the population.
• 1970 Form 2 samples contain a somewhat different set of variables than Form 1 samples.
• Approximately 744,000 household and 2,030,000 person records.

1970 1% Puerto Rico State sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic unit is the state.
• Approximately 7,460 household and 27,212 person records.

1970 1% Puerto Rico Municipio sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic units are metropolitan areas and county groups: combinations of counties totaling at least 250,000 population.
• Approximately 7,460 household and 27,212 person records.

1970 1% Puerto Rico Neighborhood sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic units are "neighborhoods" of about 4000 population (approximately the size of census tracts). The precise location of a given neighborhood is supressed; only its state is provided. Households from 380 separate neighborhoods are included in the sample.
• Neighborhood samples contain a set of additional variables giving summary statistics for the neighborhood in 1970 (e.g., percent of population age 65 or older). The extra variables are appended onto the end of the household record.
• Approximately 7,460 household and 27,212 person records.

1980 5% State sample

• 1-in-20 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the county group, which can be any combination of counties or portions of counties that total 100,000 population. The state sample privileges state identification over metropolitan area identification. Where the combination of state and metropolitan area would enable the identification of areas smaller than 100,000 population, the 1980 state sample suppresses the metropolitan area information. 
• Approximately 4,711,000 household and 11,337,000 person records.

1980 1% Metro sample

• 1-in-100 national random sample of the population. (Note, this is not a sample only of metro areas.)
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the county group, which can be any combination of counties or portions of counties that total 100,000 population. The metro sample privileges metropolitan area identification over state identification. Where the combination of state and metropolitan area would enable the identification of areas smaller than 100,000 population, the 1980 metro sample suppresses the state information. 
• Approximately 942,000 household and 2,267,000 person records.

1980 1% Urban/rural sample

• 1-in-100 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. This 1980 sample identifies urban status, and the smallest geographic units provided are urbanized areas (similar to metropolitan areas, but more specifically urban in character). Some cities are given, but no metropolitan areas; and many smaller states cannot be separately identified.
• Approximately 942,000 household and 2,269,000 person records.

1980 1% Labor Market Areas sample

• 1% random sample of the state population.
• Labor Market Areas are defined by a hierarchical cluster analysis of counties based on work-to-residence commuting patterns.
• Approximately 942,000 household and 2,269,000 person records.

1980 1% Detailed Metro/Nonmetro sample

• 1-in-100 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. This sample identifies urban and rural place status within metropolitan areas, and the smallest geographic units provided are urbanized areas (similar to metropolitan areas, but more specifically urban in character). Some cities are given, but no metropolitan areas; and many smaller states cannot be separately identified.
• Approximately 942,000 household and 2,269,000 person records.

1980 5% Puerto Rico sample

• 1-in-20 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the county group, which can be any combination of counties or portions of counties that total 100,000 population.
• Approximately 50,847 household and 160,219 person records.

1980 1% Puerto Rico sample

• 1-in-100 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the county group, which can be any combination of counties or portions of counties that total 100,000 population. 
• Approximately 10,169 household and 32,049 person records.

1990 5% State sample

• 1-in-20 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the PUMA, which can be any combination of counties or portions of counties that total 100,000 population. The state sample privileges state identification over metropolitan area identification. Where the combination of state and metropolitan area would enable the identification of areas smaller than 100,000 population, the 1990 state sample suppresses the metropolitan area information. 
• Approximately 5,528,000 household and 12,500,000 person records.

1990 1% Metro sample

• 1-in-100 national random sample of the population. (Note, this is not a sample only of metro areas.)
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the PUMA, which can be any combination of counties or portions of counties that total 100,000 population. The metro sample privileges metropolitan area identification over state identification. Where the combination of state and metropolitan area would enable the identification of areas smaller than 100,000 population, the 1990 metro sample suppresses the state information. 
• Approximately 1,106,000 household and 2,500,000 person records.

1990 3% Elderly sample

• 1-in-33 national random sample of households containing at least one person age 60 or older. 
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than 100,000 population can be identified with any geographic variable. The elderly sample follows the same geographic identification system as the 5% state sample. The most basic geographic variable is the PUMA, which can be any combination of counties or portions of counties that total 100,000 population. Like the 5% state sample, the elderly sample privileges state identification over metropolitan area identification. Where the combination of state and metropolitan area would enable the identification of areas smaller than 100,000 population, the 1990 elderly sample suppresses the metro area information. 
• In addition to PUMAs, the elderly sample identifies the state Planning Service Area (PSA) in which a household resided.
• Approximately 949,000 household and 1,855,000 person records.

1990 1% Unweighted state sample

• 1-in-100 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the PUMA, which can be any combination of counties or portions of counties that total 100,000 population. The state sample privileges state identification over metropolitan area identification. Where the combination of state and metropolitan area would enable the identification of areas smaller than 100,000 population, the 1990 state sample suppresses the metropolitan area information. 
• Approximately 1,100,000 household and 2,500,000 person records.

1990 0.5% Labor Market Areas sample

• An approximate 1-in-200 national random sample of the population.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the Labor Market Area (LMA), which can be any combination of counties.
• Approximately 1,100,000 household and 2,500,000 person records.

1990 5% Puerto Rico sample

• 1-in-20 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the PUMA, which can be any combination of counties or portions of counties that total 100,000 population.  
• Approximately 61,698 household and 177,655 person records.

1990 1% Puerto Rico sample

• 1-in-100 national random sample of the population. (Note, this is not a sample only of metro areas.)
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than 100,000 population can be identified with any geographic variable. The most basic geographic variable is the PUMA, which can be any combination of counties or portions of counties that total 100,000 population.
• Approximately 12,335 household and 35,615 person records.

2000 5% sample

• 1-in-20 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons. PUMAs do not cross state boundaries.
• Approximately 5,663,214 household and 14,081,466 person records.

2000 1% sample

• 1-in-100 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the Super-PUMA containing at least 400,000 persons. Super-PUMAs do not cross state boundaries.
• Approximately 1,237,000 household and 2,819,000 person records.

2000 1% Unweighted sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons. PUMAs do not cross state boundaries.
• Approximately 1,236,891 household and 2,808,457 person records.

2000 5% Puerto Rico sample

• 1-in-20 national random sample of the population.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons.
• Approximately 73,259 household and 189,828 person records.

2000 1% Puerto Rico sample

• 1-in-100 national random sample of the population.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons.
• Approximately 14,651 household and 38,111 person records.

American Community Survey 2000 sample

• 1-in-750 (approximately) national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than state can be identified.
• The ACS questionnaire was nearly identical to the 2000 census long form (the source for the 2000 census samples). The ACS contains several questions on involvement in government programs and a fertility question not asked in the census.
• Approximately 158,000 household and 372,000 person records.

American Community Survey 2001 sample

• 1-in-232 (approximately) national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than state can be identified.
• Approximately 483,000 household and 1,200,000 person records.

American Community Survey 2002 sample

• 1-in-261 (approximately) national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than state can be identified.
• Approximately 434,000 household and 1,075,000 person records.

American Community Survey 2003 sample

• 1-in-236 (approximately) national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than state can be identified.
• Approximately 482,000 household and 1,194,000 person records.

American Community Survey 2004 sample

• 1-in-239 (approximately) national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• No place smaller than state can be identified.
• Approximately 514,830 household and 1,194,354 person records.

American Community Survey 2005 sample

• 1-in-100 national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons. PUMAs do not cross state boundaries.
• Approximately 1,159,000 household and 2,878,000 person records.

Puerto Rico Community Survey 2005 sample

• 1-in-100 national random sample of the population.
• The data do not include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons.
• Approximately 14,407 household and 35,416 person records.

American Community Survey 2006 sample

• 1-in-100 national random sample of the population.
• The data include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons. PUMAs do not cross state boundaries.
• Approximately 1,344,000 household and 2,970,000 person records.

Puerto Rico Community Survey 2006 sample

• 1-in-100 national random sample of the population.
• The data include persons in group quarters.
• This is a weighted sample. Weights must be used to produce accurate statistics.
• The smallest identifiable geographic unit is the PUMA, containing at least 100,000 persons.
• Approximately 14,844 household and 34,746 person records.