United States. Bureau of Labor Statistics. "Nonfarm Business Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Second Quarter 1992 [Preliminary]," Productivity and Costs (August 11, 1992) : 15-15. https://fraser.stlouisfed.org/title/131/item/55821/toc/464935 , accessed on May 1, 2024.