The only study that ever reported 10% was the Kinsey study. Unfortunately, (for the activists), Kinsey's results could never be independently verified, or duplicated.
Kinsey's original study, heralded and celebrated, was found to suffer from selection bias. He deliberately chose prisoners who had experimented with homosexuality while in prison or who were locked up for homosexual behavior. Others in his sample group were prisoners who were locked up for deviant sexual crimes. This skewed the results, making the behavior seem to be much more prevalent than it is.
The homosexual lobby however, repeats the 10%, acknowledging candidly that it is fake, as 1) a lie repeated often enough becomes true, and 2) the "other side lies too".