The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU02032198
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Employment Level: Persons At Work 1 to 34 Hours, Economic Reasons: Slack Work or Business Conditions, Nonagricultural Industries [LNU02032198], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU02032198/, July 7, 2015.