MIT was elected to the Association of American Universities in 1934 and remains a research university with a very high level of research activity; research expenditures totaled $718.2 million in 2009. The federal government was the largest source of sponsored research, with the Department of Health and Human Services granting $255.9 million, United States Department of Defense $97.5 million, United States Department of Energy $65.8 million, National Science Foundation $61.4 million, and NASA $27.4 million. MIT employs approximately 1300 researchers in addition to faculty. In 2011, MIT faculty and researchers disclosed 632 inventions, were issued 153 patents, earned $85.4 million in cash income, and received $69.6 million in royalties. Through programs like the Deshpande Center, MIT faculty leverage their research and discoveries into multi-million-dollar commercial ventures.. How many years has MIT been in the Association of American Universities?