Source: U.S. Bureau of Labor Statistics
Release: Employment Situation
The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS13025670
U.S. Bureau of Labor Statistics, Persons Unemployed 15 weeks or longer, as a percent of the civilian labor force [U1RATE], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/U1RATE, April 20, 2018.