Series Is Presented Here As Two Variables--(1)--Seasonally Adjusted, 1919-1940 (2)--Seasonally Adjusted, 1948-1964. Source: J. Shiskin Of NBER, Table 6, January 29, 1965
This NBER data series m16002b appears on the NBER website in Chapter 16 at http://www.nber.org/databases/macrohistory/contents/chapter16.html.
NBER Indicator: m16002b
Release: NBER Macrohistory Database
National Bureau of Economic Research, Amplitude-Adjusted Composite Index of Leading Series, Eight Series, Weighted for United States [M1602BUSM358SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M1602BUSM358SNBR/, October 6, 2015.