Board of Governors of the Federal Reserve System (U.S.), 1935-. "Nonfinancial Business Activity - Selected Measures," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "1980-1989," Annual Statistical Digest (March 1991) : 285-290. https://fraser.stlouisfed.org/title/7/item/23495/toc/414304 , accessed on April 19, 2024.