Source: J. Shiskin At NBER, Table 6, January 29,1965
This NBER data series m16004 appears on the NBER website in Chapter 16 at http://www.nber.org/databases/macrohistory/contents/chapter16.html.
NBER Indicator: m16004
Release: NBER Macrohistory Database
National Bureau of Economic Research, Composite Index of Four Roughly Coincident Series, Amplitude-Adjusted, Unweighted for United States [M16004USM358SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M16004USM358SNBR/, October 13, 2015.