Over the past few months, the polling agency Gallup asked 121,290 American adults the question, "Do you, personally, identify as lesbian, gay, bisexual, or transgender?"
According to their findings, 3.4% said "yes," but Gallup does admit some limitations:
Gallup chose the broad measure of personal identification as LGBT because this grouping of four statuses is commonly used in current American discourse, and as a result has important cultural and political significance. One obvious limitation of this approach is that it is not possible to separately consider differences among lesbians, gay men, bisexuals, or transgender individuals. A second limitation is that this approach measures broad self-identity, and does not measure sexual or other behavior, either past or present.
Flaws aside, the findings offer some interesting details about LGBT life in the States: for example, more non-white American identified as LGBT; LGBT women are just as likely to be raising children as their heterosexual counterparts; and most of the self-identified LGBT people make less than $60,000 annually.