The National Collegiate Athletic Association (NCAA) is a nonprofit organization that regulates student athletics among about 1,100 schools in the United States, Canada, and Puerto Rico. It also organizes the athletic programs of colleges and universities in the United States and Canada and helps over 500,000 college student athletes who compete annually in college sports. The organization is headquartered in Indianapolis, Indiana. Until 1957, the NCAA was a single division for all schools. In August 1973, the current three-division system of Division I, Division II, and Division III was adopted by the NCAA membership in a special convention. Division I football was further divided into I-A and I-AA in 1978, while Division I programs that did not have football teams were known as I-AAA. In 2006, Divisions I-A and I-AA were respectively renamed the Football Bowl Subdivision (FBS) and Football Championship Subdivision (FCS). In its 2016–17 fiscal year, the NCAA took in $1.06 billion in revenue, over 82% of which was generated by the Division I men’s basketball tournament.