The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU05026642
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Not in Labor Force, Searched For Work and Available [LNU05026642], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU05026642/, June 3, 2015.