LGBT people make up 3.5% of the population, according to a Gallup survey of 120,000 adults. That figure is very close to a 2011 estimate, which put the gay and lesbian population at just 1.7%, and the number of bisexuals (who are mostly women) at 1.8%, for a total of 3.8%.
But most Americans have no idea how many of their countrymen are gay. When asked to take a guess by Gallup in 2011, most said 25% or above. Which is utterly wrong, it transpires.
The numbers in Gallup's survey are based on self-reports, so some might question whether the true number is significantly higher. In the 2011 study, 8.2% of Americans admitted they had had same-sex sexual relations, and 11% reported some feeling of sexual attraction. Those numbers mean that millions of Americans have had sex with same-sex partners, but don't identify as gay or bisexual.
Via Gallup and UCLA's Williams Institute.