Increased productivity is a key to a healthy and thriving economy. Consequently, the trend in productivity, economywide, is one of the most closely watched of our common economic performance indicators. Agriculture, in particular, has been a very successful sector of the U.S. economy in terms of productivity growth. The U.S. farm sector has provided an abundance of output while using inputs efficiently. Agricultural productivity growth has been an important source of U.S. economic growth throughout the century, but the years since 1940 have seen an even faster growth in agricultural productivity. The annual average increase in productivity from 1948 to 1994 was 1.94 percent. This reflects an annual growth in output of 1.88 percent per year and an actual decline in agricultural inputs of 0.06 percent per year. This report describes changes in U.S. agricultural productivity, and its output and input components, for 1948-94. The report also discusses factors that have affected productivity trends and provides detailed, technical information about the USDA system for calculating productivity.