Source: Superintendent, Pittsburgh, Bur. Of Build. Insp., Dept. Of Public Safety (By Correspondence).
This NBER data series a02064 appears on the NBER website in Chapter 2 at http://www.nber.org/databases/macrohistory/contents/chapter02.html.
NBER Indicator: a02064
Release: NBER Macrohistory Database
National Bureau of Economic Research, Value of Permits For Additions and Alterations for Pittsburgh, PA [A02064US38300A550NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A02064US38300A550NNBR/, July 30, 2015.