NBER Computed Data By Adding Male And Female Unemployed, 20 Years And Older From Figures Listed In The Sources. Source: Data Were Derived By NBER, Data For 1948-1961: From "Employment And Earnings", February 1962, Summary Tables; Data For 1962-1963: Special Labor Force Reports 31 And 43; Data For 1964-1965: Monthly Report On The Labor Force (Except Data For April-June Which Come From The Bureau Of The Census.)
This NBER data series m08301 appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html.
NBER Indicator: m08301
Release: NBER Macrohistory Database
National Bureau of Economic Research, Number of Unemployed, Twenty Years and Older for United States [M08301USM175NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M08301USM175NNBR, February 8, 2016.