The Index Was Computed By NBER From Figures Showing The Percentage Changes Between Successive Months For Changing Groups Of Identical Firms. Source: Computed By NBER From Figures Supplied By The Federal Reserve Bank Of Chicago (1923-1937 Data) And The U.S. Department Of Commerce (1938)
This NBER data series m06047 appears on the NBER website in Chapter 6 at http://www.nber.org/databases/macrohistory/contents/chapter06.html.
NBER Indicator: m06047
Release: NBER Macrohistory Database
National Bureau of Economic Research, Index of Wholesale Trade Sales, Drugs for FRB - Chicago District [M06047USFRB07M355NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M06047USFRB07M355NNBR/, July 30, 2015.