The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU03023557
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Unemployment Level: Reentrants to Labor Force [LNU03023557], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU03023557/, July 1, 2015.