Series Is Presented Here As Three Variables--(1)--Seasonally Adjusted Data, 1929-1942 (2)--Seasonally Adjusted Data, 1940-1946 (3)--Original Data, 1947-1966. Source: National Industrial Conference Board, Published By G.H. Moore, Business Cycle Indicators, Vol. Ii, P. 35 And 123.
This NBER data series m08292a appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html.
NBER Indicator: m08292a
Release: NBER Macrohistory Database
National Bureau of Economic Research, Unemployment Rate for United States [M0892AUSM156SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M0892AUSM156SNBR/, August 4, 2015.