Source: U.S. Bureau Of Census, NBER Series 08280 Divided By Implicit Price Deflators For Gross National Product.
This NBER data series q08321 appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html.
NBER Indicator: q08321
Release: NBER Macrohistory Database
National Bureau of Economic Research, Gross National Product, Income Estimate In Constant Dollars for United States [Q08321USQ008SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/Q08321USQ008SNBR/, July 7, 2015.