Same-sex activity also appears to be on the rise, or at least less taboo (rather than through face-to-face interviews, the new survey was carried out online, a method believed to encourage more open and honest responses). While only about 7% of men and women identified themselves as "other than heterosexual", far more said they had engaged in some form of sexual activity with a member of the same sex. Nearly 15% of women in their 30s, for example, reported having performed oral sex on another woman at least once in their lifetime, while 13% of men over 40 said they had done the same to another man and 50% of men aged 50-59 said they had received it.

http://www.guardian.co.uk/lifeandstyle/2010/oct/05/sex-us-american-attitudes-survey