Source: J. Shiskin At NBER, January 4, 1965
This NBER data series m16020 appears on the NBER website in Chapter 16 at http://www.nber.org/databases/macrohistory/contents/chapter16.html.
NBER Indicator: m16020
Release: NBER Macrohistory Database
National Bureau of Economic Research, Diffusion Index, Average Workweek, Twenty-One Manufacturing Industries, Nine Month Span for United States [M16020USM509SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M16020USM509SNBR/, August 2, 2015.