Study finds Americans are having less sex than they used to, and technology might be to blame

If you think your sex life isn't what it once was, you're not alone. People in the U.S. are having less sex today than they did generations ago, and a new study suggests that marriage may be part of the problem.

Married people typically had sex 73 times a year in 1990, researchers report in the Archives of Sexual Behavior. But by 2014 married couples were having sex just 55 times a year, trailing single people who had sex 59 times a year.

As a rule, unpartnered people used to have less sex, on average, compared to those who were married or living together, researchers note.

SEE ALSO: Scientists identify gene that could halt sudden deaths of teens

"Some of this is due to age - people get married later now," said lead study author Jean Twenge, a psychology researcher at San Diego State University. "But even when we take age into account, the marriage advantage in sexual frequency is smaller than it once was."

For unmarried people, sexual frequency increased from 1989 to 2002, perhaps because of loosening norms about premarital sex, Twenge added by email. But then, around 2008, their sexual frequency started to slide - and both married and unmarried people started having sex less often.

"That might be because smartphones premiered in 2007, Netflix streaming video in 2007 and YouTube in 2006," Twenge said.

RELATED: Find out which states are most sexually active

"Our entertainment is more entertaining, and more on-demand than it once was," Twenge added. "There are a lot more things to do at 10 p.m. at home than there used to be."

To examine shifts in national sex habits, researchers looked at survey data collected from 1972 to 2014 on a nationally representative sample of 56,859 adults.

SEE ALSO: Neanderthals 'discovered' aspirin and penicillin nearly 50,000 years ago

Among other things, participants answered questions about how often they had sex in the past 12 months, and demographics like their education level and marital status.

As recently as 2002, the average American adult had sex about 64 times a year, but by 2014 that declined to 53 times a year. The decrease in sexual frequency was largest among those with a college degree, people in the South and married or divorced individuals.

One limitation of the study is that the survey didn't specify what types of sex it was asking about, making it possible that some respondents might have been counting just vaginal-penile intercourse while others might have included oral or anal sex in their tally, the authors note. The survey also didn't look at masturbation.

Importantly, the study also doesn't prove that more sex necessarily makes people happier, noted Christian Joyal, a researcher at the University of Quebec at Trois-Rivieres who wasn't involved in the study.

RELATED: The most sexually active countries are ...

"It is clear that couples are happier, in general, than singles, especially for middle-agers, for many reasons," Joyal said by email. "Among them is interpersonal complicity and sexuality - so as long as interpersonal sexuality is concerned, quality, much more than quantity is important."

One concern, though, is that married couples - especially with kids at home - are working longer hours and facing more intense financial pressures that may put a damper on their sex lives, said Michael Aaron, a sex therapist in private practice in New York City who wasn't involved in the study.

"As the gap is widening between rich and poor and the middle class is disappearing, more people have to spend more time working, sometimes even two or three jobs, just to stay afloat," Aaron said by email. "That doesn't leave much time or energy for sex."

Worldwide, fewer people are getting married and having kids, and people are also having less sex, said David Ley, author of The Myth of Sex Addiction.

"The trends in this study aren't unique to the U.S.," Ley, who wasn't involved in the study, said by email. "Are they a reason to be concerned? Who knows? Perhaps the world needs fewer humans right now, until we can start exporting colonists to other planets."

SOURCE: Archives of Sexual Behavior, online March 6, 2017.