This figure illustrates the decline in prevalence of HPV6, 11, 16, and 18 among U.S. girls ages 14 to 19 following HPV vaccine introduction. The first HPV vaccine was recommended for adolescent girls in 2006. In 2003-2006, the three years that preceded this recommendation, 11.5 percent of 14- to 19-year old U.S. girls had one of these HPV types. In 2007-2010, the three years following the HPV vaccine recommendation for adolescent girls, 5.1 percent of 14- to 19-year old U.S. girls had one of these HPV types.