That number doesn't mean much without the percentage of heterosexual(or non-"gay") teenagers who were sexually abused before age 13. Furthermore, it would be appropriate to break those numbers down into male and female, because male homosexuality and female homosexuality have significant differences in their pathogenesis and prevalence. (Yes, I used the word "pathogenesis," the heck with the code of political correctness.) But I wouldn't be surprised if the CDC (which is a federal government agency, after all) would refuse to release statistics that could be considered detrimental to the causes of gay activists.
The survey is very damaging to the gay activists who want to blame Christians for these children's depression etc. when a lot of them are probably depressed because of abuse (and if you read the whole article, abuse includes forced intercourse) which is why I have yet to see it reported in the MSM...