Series Is Presented Here As Two Variables--(1)--Original Data, 1909-1926 (2)--Original Data, 1922-1938. Source: P.H. Douglas, Real Wages In The United States, 1890-1926, P.362.
This NBER data series a08057a appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html.
NBER Indicator: a08057a
Release: NBER Macrohistory Database
National Bureau of Economic Research, Annual Salaries of Clerical Employees for Pennsylvania [A0857AUS000PAA052NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A0857AUS000PAA052NNBR/, July 5, 2015.