Virgins in the United States.

13.9% of men and 8.9% of women between the ages of 25 to 45 have never had sex.

Via Metafilter, where there are some comments like this....

I watch the people around me find relationships so easily (I know it's *never* easy - but believe me, however difficult it is for you, it's all but insurmountable for me) and I wonder, night after night, month after month, year after year, what I'm doing wrong. it's hard not to wonder whether there's something fundamentally, immutably wrong with *me*. it's hard not to wonder whether sex and romantic love are simply things which aren't *for* me - things which the universe has seen fit to make available to others, but not to me. I know that doesn't make sense, but that's often how it feels.

it's hard not to feel resentful watching others take it all for granted, and to be asked why I don't just [find a girlfriend/get laid/go on some dates], the same way you'd suggest that I make a sandwich if I complain that I'm hungry - like I can just snap my fingers and make those things happen. I don't know *how* to make a sandwich. that may sound ridiculous to you - *everyone* knows how to make a sandwich! but as basic and instinctive as it may seem, there was a specific time, long ago, when someone showed you for the first time *how* to make a sandwich, right? well, I never learned. and now everyone insists that there *isn't* anything to learn; it's just something that people *know* how to do - and so they couldn't teach me even if they wanted to.

I'm not talking about mechanics; I'm actually relatively comfortable with that. I'm not even talking about the complexities of relationships - once I'm *in* one, I do well enough. I'm just talking about everything between here and there. it may be something *you* can just *do*, like making a sandwich. it's a dense jungle full of vipers and quicksand for me.

ADDED: As the commenters at the first link point out, it was a study restricted to unmarried Americans.