The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU01327659
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Civilian Labor Force Participation Rate: Less than a High School Diploma, 25 years and over [LNU01327659], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU01327659/, September 4, 2015.