The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU02026620
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Multiple Jobholders as a Percent of Employed [LNU02026620], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU02026620/, July 7, 2015.