This Index Is Based On Reports Of A Sample Of Firms Ranging From 261 In February 1949 To 793 In April 1958. Source: G.H. Moore, Business Cycle Indicators, Vol. 2, NBER, P. 167
This NBER data series q16099a appears on the NBER website in Chapter 16 at http://www.nber.org/databases/macrohistory/contents/chapter16.html.
NBER Indicator: q16099a
Release: NBER Macrohistory Database
National Bureau of Economic Research, Diffusion Index, Manufacturers' Sales, 800 Concerns, Four Quarter Span for United States [Q1699AUSQ509NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/Q1699AUSQ509NNBR/, October 8, 2015.