Jon Millward explored porn star demographics using a data scrape from the Internet Adult Film Database: hair color, race, and birthplace, among other things. (There aren't any dirty pictures, but there's some terminology that might be NSFW.)
The average measurements?
I thought that maybe if the women are overestimating how light they are, they might also be a bit too generous when reporting their measurements. It turns out they probably aren’t though, because the most common bra size for a female porn star is a surprisingly handleable 34B. Not double-D, not even a D. Double-D actually came in 4th, behind B, C and D. The most common set of measurements for the women was 34–24-34.
So, if the average female porn star is a 5'5" woman who weighs 117lbs and has B-cup breasts, what colour is her hair? Blonde, presumably, if my friends' guesses were anything to go by.
Apparently not. Dark-haired porn stars outnumber blonde ones almost 2-to-1.
Millward doesn't look at changes over time a whole lot, but if the BMI of Playboy playmates is any indicator, I bet those measurements have changed over the years.