Some women have 'em; some women don't. Personally, I'm suspicious of any attempt to assign numbers or percentages here because I think it is impossible to obtain a statistically significant random sample. Women who feel comfortable talking about their sexual responses to pollsters will likely tilt things to the side of those who are having multiple orgasms -- if for no other reason than that they are more comfortable experimenting and taking risks. And what, after all, could be riskier than talking about your sex life with an absolute stranger?
Many sex experts think you can teach yourself to have multiple orgasms by spending time alone with your own body (and perhaps a vibrator), experimenting with different types and rhythms of touch. This is a pretty fun way to while away a rainy afternoon, particularly if you stock some ice cream in the freezer to eat afterward!
But sexual release should not be measured in quantity, but in quality. The key is how satisfied you feel when you get out of bed with your boyfriend. If you feel pretty damn good after just one orgasm, then probably once is enough. There's no point in ruining a good thing.
Patrizia DiLucchio has been a nurse, model, topless dancer, criminologist, postal clerk, health policy analyst, Hollywood executive, editor, writer and index entry in The Joy of Cybersex