576. Column 31. Number of Weeks Worked in 1939 (Equivalent Full-Time Weeks). There must be an entry in col. 31 for every person 14 years old and over, except inmates of the specified institutions (see par. 504), even though during the week of March 24-30, the person was neither at work, with a job, nor seeking work. Col. 31 is to be left blank only for the inmates of the specified institutions ("Inst." in col. 21) and for persons under 14 years of age.