The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS15000025
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Not in Labor Force: 20 years and over, Men [LNS15000025], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNS15000025/, July 7, 2015.