1. Approximately half of all Americans say they have sex at least once a week.

An international survey conducted by Harris Interactive for the Durex condom company also found that Nigerians and Americans are tied neck-and-neck in sexual frequency: 53 percent of Nigerians and Americans claim to do it at least once a week, compared to 78 percent of Chinese and a whopping 87 percent of Greeks. Who has more fun? At 67 percent, Nigeria's sexual-satisfaction rate topped the survey's 26 nations, compared to 40 percent in Britain and Australia, 25 percent in France, and 15 percent in Japan. "The Japanese have paper walls in their houses, live with their parents, and work long hours," surmises sexologist Dr. Susan Block, who has been featured on HBO's Real Sex and Cathouse.

Carl Latkin et al. (2008): The Durex Sexual Wellbeing Global Survey

2. Men have 16 percent more sex than women do.

According to a University of Chicago study, men claim to have sex 66.5 times a year, while women claim to have sex 57.2 times a year. That might be because men traditionally overreport their sexual activity while women traditionally underreport theirs. Kinsey Institute sexual health educator Debby Herbenick says it might also be because "men are socialized to feel that sex is OK, while women are still being socialized to put on the brakes."

James Davis et al. (2006): American Sexual Behavior: Trends, Socio-Demographic Differences, and Risk Behavior. National Opinion Research Center/University of Chicago General Social Survey Topical Report No.

3. Jews and agnostics are 20 percent more sexually active than Catholics and Protestants.

The study that produced this statistic also found that Baptists have slightly more sex than the national average, while "Presbyterians and Lutherans are slightly below average." "There's more shame and guilt with the Christian religions," says Herbenick, who is also the author of Because It Feels Good: A Woman's Guide to Sexual Pleasure and Satisfaction. "The Jewish religion tends to be more permissive about sexuality." Another study found that over twice as many observant married Jewish women reported having sex three to six times per week as married women in general.

John Robinson and Godbey, G. (1998): No Sex, Please ... We're College Graduates. American Demographics, 20 (18-23)

Ellen Labinsky et al. (2009): Observant Married Jewish Women and Sexual Life: An Empirical Study. Conversations 5, 37-59 ---

4. People with Associate in Arts degrees have 32 percent more sex than people with advanced college degrees and people who did not finish high school.

According to a University of Chicago study, those with graduate degrees and those who never finished high school are tied, both groups claiming to have sex on average about once a week or 52 times per year. But those with Associate in Arts degrees claim to have sex 69.5 times per year.

James Davis et al. (2006): American Sexual Behavior: Trends, Socio-Demographic Differences, and Risk Behavior. National Opinion Research Center/University of Chicago General Social Survey Topical Report No. 25

5. Miami residents are 59 percent more sexually active than residents of Minneapolis-St. Paul.

Conducted by the research firm StrategyOne for Trojan Brand Condoms, the Degrees of Pleasure Study examined "Americans' sexual habits and preferences as they relate to temperatures and weather phenomena." On average, Miamians claim to have sex 102 times a year, compared to New Yorkers' 85 times, San Franciscans' 72 times, and Twin Cityites' 64 times. Miamians also reported the nation's longest sex sessions: 35 minutes on average, compared to Seattleites' 27, Chicagoans' 26, and Phoenixers' 25.

Trojan's Degrees of Pleasure Study (2010)

6. African-Americans have 8.2 percent more sex than Caucasians.

The study that produced this statistic found that, on average, African-Americans reported having sex 65.8 times per year, while Caucasians reported having sex 60.8 times a year. Another study found that 25 percent of African-American men claim to spend at least an hour on each of their sexual encounters, compared to 19.4 percent of white men and 15.9 percent of Hispanic men. "I would be surprised if that many men really spend that long having sex," Herbenick says. "People have lives." She's intrigued by data examining different types of sex acts by race. "White Americans are more likely to engage in oral sex, and in some parts of the country Hispanics are more likely to engage in anal sex, perhaps as a way to preserve vaginal virginity."

James Davis et al. (2006): American Sexual Behavior: Trends, Socio-Demographic Differences, and Risk Behavior. National Opinion Research Center/University of Chicago General Social Survey Topical Report No. 25

Edward Laumann et al. The Social Organization of Sexuality: Sexual Practices in the United States. Chicago: University of Chicago Press, 1994, p. 94 ---

7. Smokers are 10 percent more sexually active than nonsmokers.

According to the study that produced this finding, drinkers are 20 percent more sexually active than nondrinkers, and those who both smoke and drink are almost 200 percent more sexually active than those who do neither. "Drinking is one of the few genuine aphrodisiacs," says Block, who is also the author of The Ten Commandments of Pleasure: Erotic Keys to a Healthy Sexual Life. "It lowers your inhibitions, so people who have been drinking have sex with people they would never have sex with if they weren't drinking." Not that that's a good thing. "Smoking is not an aphrodisiac, but people who smoke these days are risk-takers." Aware of nicotine's lethal powers, "they smoke to look sexy and feel socially relaxed."

John Robinson and Godbey, G. (1998): No Sex, Please ... We're College Graduates. American Demographics, 20 (18-23)

8. People who rarely go to church have 31 percent more sex than people who regularly go to church.

"Extremely devout people are also less likely to masturbate and use vibrators," Herbenick says. The lead author of the study that produced this statistic writes, "Religion exercises a traditional restraint on sexual behavior. Those who attend church regularly are less likely to a) become sexually active, b) have multiple and casual partners, and c) among the married, have sexual partners other than their spouses."

James Davis et al. (2006): American Sexual Behavior: Trends, Socio-Demographic Differences, and Risk Behavior. National Opinion Research Center/University of Chicago General Social Survey Topical Report No. 25

9. People with a strong preference for jazz are 30 percent more sexually active than the average American.

"Liking other types of music, such as rock or rap, was unrelated to sexual activity," write the authors of the psychology textbook from which this statistic is drawn. They hasten to add that liking jazz doesn't automatically make us into sex magnets: "Remember, a correlation between two factors does not necessarily indicate causality." Then again, sometimes it does.

Don Hockenbury and Hockenbury, Sandra. Psychology. New York: Worth Publishers, 2010, p. 26

10. Artists and poets have as many as 233 percent more sexual partners than people who aren't artists or poets.

According to the study that produced this result, the more involved in the arts an individual is, the more partners he or she reportedly has. "Artistic communities tend to be more tolerant, liberal, progressive, and permissive in terms of sexual attitudes than other communities," says Herbenick. At Indiana University, where she teaches, "theater majors and math majors really do talk differently about their sexual lives." The researchers whose study produced this statistic theorize that artists' "impulsive noncomformity" and tendency to have "unusual experiences" sets them apart and "can be very attractive."

Daniel Nettle and Clegg, Helen (2005): Schizotypy, Creativity, and Mating Success in Humans. Proceedings of the Royal Society, 273(1586), 611–615

11. Teenage girls are 6.5 percent more sexually active than teenage boys.

The boys catch up later. But in those early years, "girls are getting more offers," Block says. "They're at the very beginning of their fertility, which makes them more desirable to men and women of all ages. It's a sad statistic in a way, because teen girls could use more time getting to know their bodies" before getting started. Teen boys, meanwhile, "are at the lifetime height of their sexual desire, yet people aren't that attracted to them. Generally, our society shuns the sexuality of teenage boys."

Danice Eaton et al. (2010): Department of Health and Human Services/Centers for Disease Control and Prevention Youth Risk Behavior Surveillance System, Morbidity and Mortality Weekly Report, 59 (SS5)

12. Twenty-two percent more homosexual male couples who have been together for two years or less have sex at least three times a week than heterosexual couples who have been together for two years or less.

In other words, newly formed gay couples are getting it on more often than their straight counterparts—unless those counterparts are lesbians. Thirty four percent more homosexual male couples who have been together for two years or less have sex at least three times a week than lesbian couples who have been together for two years or less. Another study found that homosexual and bisexual men have more partners than heterosexual men. The frequency of gay male sex has been a political football for decades as antigay pundits pontificate about promiscuity. "Gay men tend to have more sex than straight men," Herbenick says, largely because gay male sex involves "two people who are biologically more likely to have more sex than women are."

John Harvey et al. (2004): The Handbook of Sexuality in Close Relationships. Mahwah, NJ: Lawrence Erlbaum Associates, p 361

Benjamin Breyer et al. (2010): The Impact of Sexual Orientation on Sexuality and Sexual Practices in North American Medical Students. Journal of Sexual Medicine, 7 (7), 2,391-2,400

13. Children whose parents read to them less than once a week are 33 percent more likely to be sexually active when they become teenagers than children whose parents read to them at least once a week.

This statistic appears in a study sponsored by the Institute of Marriage and Family Canada, which is linked with the evangelical Christian group Focus on the Family, so the researchers' potential bias needs to be taken into account. "How parents choose to interact with their children has a lasting impact," write the study's authors, who also found that teenage girls whose parents drink to excess at least twice a year are 38 percent more likely to be sexually active than the national average, and children of nonsmokers are 15 percent less likely be sexually active than the national average.

Peter Jon Mitchell (2009): How Parental Influence Impacts Teen Sexual Activity. Ottawa: Institute of Marriage and Family Canada

14. Men over 70 years old have 215 percent more sex than women over 70 years old.

This disparity is largely due to the fact that so many women outlive their partners. It also reflects the effects of menopause and body image on female desire. "I know as a therapist that when my female clients don't want to have sex, it's often because they feel badly about how they look," says Block. While our culture lets men feel attractive well into old age, it's crueler to women, Betty White notwithstanding.

James Davis et al. (2006): American Sexual Behavior: Trends, Socio-Demographic Differences, and Risk Behavior. National Opinion Research Center/University of Chicago General Social Survey Topical Report No. 25

15. Women of what doctors consider normal weight are 30 percent more likely to have had sex in the past year than obese women.

This study, which found the frequency of sex for both genders declining as body-mass index increases, was performed in France. Other studies comparing weight and sexual activity reveal conflicting results, perhaps reflecting different attitudes toward body weight in different regions and communities. "The obvious thing is that most people don't find obese people attractive," Block says. "Moreover, being obese is tiring and sex is an energetic activity," thus arguably an ordeal. Also from the French study: "Obese women aged 18-29 were three times as likely to report having met a sexual partner through the Internet than those with a normal body-mass index."

Nathalie Bajos et al. (2010): Sexuality and Obesity, a Gender Perspective. British Medical Journal, 340, c2573

Anneli Rufus is the author of many books, including Party of One: The Loners' Manifesto and the Nautilus Award-winning Stuck: Why We Don't (or Won't) Move On, and the coauthor of still more, including Weird Europe and The Scavengers' Manifesto. Her books have been translated into numerous languages, including Chinese and Latvian. In 2006, she won a Society of Professional Journalists award for criticism.