>> The 4% is point prevalence. If you take lifetime experience it is higher. At least 5%.
Proof?
Not flimsy studies, mind you. Proof?
All surveys are likely to underestimate the actual prevalence of homosexuality because, fearing discrimination and stigma, many gay respondents are reluctant to tell a stranger (even anonymously) that they are homosexual (e.g., Villarroel et al., 2006). Recognizing this limitation, most research with probability samples suggests that at least 3-6% of the US adult male population is homosexual, with somewhat fewer females (Fay, Turner, Klassen, & Gagnon, 1989; Hatfield, 1989; Laumann, Gagnon, Michael, & Michaels, 1994; Lever & Kanouse, 1996; Rogers & Turner, 1991).
The source is: HERE
The above figures are problematical. It all depends upon the homosexual acts included-fellatio, fondling, sodomy, mutual masturbation and so forth. Some more restrictive definitions get a point prevalence of 2% while others get 6%. 4% is what is usually used.
If you are interested all you need do is Google "Incidence of male homosexuality" and you can read for hours.