The U.S. pork industry registered another year of strong productivity gains in 2012. Since 1990, pork production has increased by more than 52 percent, while the U.S. inventory of breeding sows has decreased by more than 15 percent. A primary source of pork industry productivity gains is increasing litter rates, which have more than offset declining sow numbers. Because of the growth in sow efficiency, the industry can produce the same or greater number of pigs with fewer sows. The dramatic increase in litter rates beginning in 2007 is mostly attributed to advances in breeding herd genetics and improvements in the management and care for sows during gestation and farrowings. Since 2007, the hog industry has enhanced its selective breeding methods to develop sows that produce and nurture more piglets. At the same time, a larger share of swine producers utilized the latest housing technologies and labor practices, improving the comfort and survivability of sows and their piglets, hence contributing to larger hog production. This is an update of a chart from Livestock, Dairy, and Poultry Outlook, LDPM-220, October 2012.