The Data Represent Manufactured Iron And Steel Products Including Machinery And Vehicles. Source: Unpublished Tabulation. For Description And Coverage Of Series See Robert. E. Lipsey, Price And Quantity Trends In The Foreign Trade Of The U.S., N.B.E.R., 1963, Pp. 289-95.
This NBER data series q07056 appears on the NBER website in Chapter 7 at http://www.nber.org/databases/macrohistory/contents/chapter07.html.
NBER Indicator: q07056
Release: NBER Macrohistory Database
National Bureau of Economic Research, Quantity Index of Exports of Iron and Steel for United States [Q07056USQ324NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/Q07056USQ324NNBR/, November 25, 2015.