The right frequency for sex is as often as you both enjoy it," says, M.D., Ph.D., in The Joy of Sex. "Don't be compulsive about frequency (or worried if friends say theirs is lower than yours). You aren't being scored." All of which seems like eminently sane advice in a culture obsessed with scoring everything, from bowling championships to orgasms per week. Still-let's face it - everybody is interested. It's normal to wonder if you're normal.

A 1991 study by the National Opinion Research Center at the University of Chicago found that American adults reported having sexual intercourse an average of 57 times in the preceding year (about once a week). Married people were more active than singles, reporting having intercourse 67 times in the preceding year. And as in all other sex surveys, there was a steady decline with age, dropping from 78 times a year (three times every two weeks) for those under 40 to eight times a year (once every six weeks or so) for those over 70.

But this is only the frequency with which people have intercourse. When you include all varieties and permutations of human sexual behavior (including masturbation, wet dreams, mutual sex play that includes orgasm but not intercourse and everything else), the numbers are considerably higher. The late Dr. Alfred Kinsey found that the average white American man under age 30 had an orgasm (by whatever means) a little more than three times a week. When you consider the total male population of all ages, he found, the rate is closer to twice a week. (Oddly enough, the frequency with which married women have sex is often reported to be a little lower than that of married men. How is that possible? The University of Chicago researchers concluded that both men and women lie, at least a little, about sex - men inflating, women deflating, their sexual activities.)