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-. "1987," Annual Statistical Digest (October 1988) : 126-126. https://fraser.stlouisfed.org/title/7/item/23493/toc/193469 , accessed on April 19, 2024.