The Last Two Years Were Computed By Dividing The Retail Value In A Given Year By The Retail Value In 1926 (See"Agricultural Statistics", 1943, Table 505.) Source: Bureau Of Agricultural Economics, "Price Spread Between The Farmer And The Consumer" By Richard O. Been And Frederick V. Waugh, 1936, And Supplement To That Report In 1941
This NBER data series a04184 appears on the NBER website in Chapter 4 at http://www.nber.org/databases/macrohistory/contents/chapter04.html.
NBER Indicator: a04184
Release: NBER Macrohistory Database
National Bureau of Economic Research, Index of Retail Price of 58 Foods for United States [A04184USA336NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A04184USA336NNBR/, September 5, 2015.