The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS12026620
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Multiple Jobholders as a Percent of Employed [LNS12026620], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNS12026620/, July 5, 2015.