HIV Prevalence Among Youth
"In 2009, youths (defined in this report as persons aged 13–24 years), who represented 21% of the U.S. population, comprised 6.7% of persons living with HIV. More than half (59.5%) were unaware of their infection, the highest for any age group (1)."
Centers for Disease Control, "Vital Signs: HIV Infection, Testing, and Risk Behaviors Among Youths - United States," Morbidity and Mortality Weekly Report, Vol. 61, No. 47 (Atlanta, GA: CDC, Nov. 30, 2012), p. 971.