Data For October 1920, April-September 1921, And May-November 1926 Were Significantly Effected By Coal Strikes And Work Stoppages. Source: National Federation Of Iron And Steel Manufacturer'S, The Iron And Coal Trades Review, January 14, 1921, P. 48 And Later Issues.
This NBER data series m01133aa appears on the NBER website in Chapter 1 at http://www.nber.org/databases/macrohistory/contents/chapter01.html.
NBER Indicator: m01133aa
Release: NBER Macrohistory Database
National Bureau of Economic Research, Pig Iron Production for Great Britain [M013AAGBM576NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M013AAGBM576NNBR/, July 28, 2015.