This slide shows the distribution of transmission categories among AIDS cases diagnosed in 2006. Approximately 43% of the 36,790 AIDS cases diagnosed in 2006 among adults and adolescents were attributed to male-to-male sexual contact. An additional 5% were attributed to male-to-male sexual contact and injection drug use. Injection drug use accounted for 18% of AIDS incidence, and high-risk heterosexual contact accounted for another 32%. The data have been adjusted for reporting delays and cases without risk factor information were proportionally redistributed.