Data Show Changes In Freight Car Rates Of Fifty Representative Agricultural Products. Source: U.S. Department Of Agriculture, Division Of Statistical And Historical Research, Yearbook, 1923, P. 1177; 1926, P. 1248.
This NBER data series m03013 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03013
Release: NBER Macrohistory Database
National Bureau of Economic Research, Freight Rate Index for United States [M03013USM324NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M03013USM324NNBR/, July 29, 2015.