Data Are The Antilog Of The Figures Found In The Source. Data Are For Daily Averages. Source: F.R. Macaulay, The Movement Of Interest Rates, Bond Yields, And Stock Prices In The U.S. Since 1856, NBER, 1938, Table 31, Column 2.
This NBER data series m01130aa appears on the NBER website in Chapter 1 at http://www.nber.org/databases/macrohistory/contents/chapter01.html.
NBER Indicator: m01130aa
Release: NBER Macrohistory Database
National Bureau of Economic Research, Pig Iron Production for United States [M010ADUSM561SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M010ADUSM561SNBR, May 5, 2016.