porn isn't real, no-one lasts over half an hour in real life. its full of edits and cuts.
secondly, im suprised a lot of people are saying an average of 20/40 minutes! unless you're counting foreplay?
The actual deed on average, is 3 minutes, assuming you're sober, have no condom on and aren't on Viagra or similar. It seems as though people are just trying to sound impressive, boasting about how long they can last, but it just sounds ridiculous.
My partners length can vary between 2-5 minutes. He one of those go at it really fast people though, which is a little disappointing. If he slowed down a little then maybe he'd hit 7 minutes, but unless he's being sensual about it rather than just shoving it in and out, i'm not going to enjoy it anyway! If you add foreplay to that, then the whole act is averaging 20-30 minutes.