The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS13008756
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Number of Civilians Unemployed for 5 to 14 Weeks [UEMP5TO14], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/UEMP5TO14/, September 3, 2015.
FRED BlogA long-term unemployment problem