United States. President and Council of Economic Advisers (U.S.). "Productivity and Related Data, Business and Nonfarm Business Sectors," in United States. President and Council of Economic Advisers (U.S.). "2015," Economic Report of the President (2015) : 408-408. https://fraser.stlouisfed.org/title/45/item/492446/toc/505660 , accessed on April 3, 2024.