The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS12032199
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Employment Level: Part-Time for Economic Reasons, Could Only Find Part-Time Work, Nonagricultural Industries [LNS12032199], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNS12032199/, September 1, 2015.