From January, 1950 To April, 1955, These Figures Refer To Percent Reporting Committments 60 Days Or Longer In Total Buying Of All Types (No Classification Was Made). Starting May, 1955, Figures Refer To The Buying Policy Of Production Materials Only. Source: National Association Of Purchasing Agents, Bulletins--First Issue Of Each Month Showing "Business Survey"
This NBER data series m06098 appears on the NBER website in Chapter 6 at http://www.nber.org/databases/macrohistory/contents/chapter06.html.
NBER Indicator: m06098
Release: NBER Macrohistory Database
National Bureau of Economic Research, Buying Policy, Production Materials, Percent Reporting, Commitments 60 Days Or Longer for United States [M06098USM156NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M06098USM156NNBR/, September 1, 2015.