Series Is Presented Here As Two Variables--(1)--Seasonally Adjusted Data, 1919-1940 (2)--Seasonally Adjusted Data, 1948-1964. Source: J. Shiskin At NBER, Table 5, January 25,1965
This NBER data series m16008b appears on the NBER website in Chapter 16 at http://www.nber.org/databases/macrohistory/contents/chapter16.html.
NBER Indicator: m16008b
Release: NBER Macrohistory Database
National Bureau of Economic Research, Adjusted Rates of Change of Composite Index of Six Roughly Coincident Series for United States [M1608BUSM156SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M1608BUSM156SNBR/, July 6, 2015.