The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU03327708
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Special Unemployment Rate: Unemployed and Marginally Attached Workers [U5RATENSA], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/U5RATENSA/, July 2, 2015.