The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU01373765
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Civilian Labor Force Participation Rate: Men, Veterans, World War II or Korean War or Vietnam Era, 18 years and over [LNU01373765], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU01373765/, July 6, 2015.