I expect it may not be more than 2%, at least openly, in the heartland in part because so many move to the major cities—and so that number seems right to many Freepers, but for those of us in blue-state cities the percentages are much different.
2% is grossly exaggerated. I think the number is closer to 0.1% based on the ratio of gay to straight marriages in states like Massachusetts.
Like the large number of homeless people debunked long ago, the numbers of gays has overstated to suit the leftist political agenda.