The Centers for Disease Control and Prevention is the latest group to attempt to estimate just how many people identify as a sexual orientation other than heterosexual. According to the CDC's National Health Interview Survey, the first broad government survey of sexual orientation, just under 3 percent of Americans identify as gay, lesbian and bisexual. Gays and lesbians make up 1.6 percent of the survey, bisexuals make up 0.7, and 96.6 percent of Americans identify as straight, based on a sample size of 33,557 adults between the ages of 18 and 64.
As The Washington Post wrote, from a health care point of view, identifying sexuality is an important step towards identifying the unique health needs of the LGBT community. But as far as quantifying how many Americans aren't heterosexual, the survey leaves something to be desired. It doesn't ask about respondent's gender identity and, as The Post noted, a small percentage of people needed more options: "an additional 1.1 percent declined to answer, responded 'I don’t know the answer' or said they were 'something else.'"
The survey comes up with a number that's lower than the 3.5 to 4 percent figure found in other surveys. And as we've seen from past surveys, what's asked matters. Specifically, the broadness of the answers available to respondents makes a difference.