Why are Americans having less sex?

Lovemaking. Banging. Sleeping. Nookie. Whoopie. Procreating. Knocking boots. F-dash-dash-dashing. No matter what you call having sex, you’re doing it less, America.

According to a new study released in the Archives of Sexual Behavior, adults in the U.S. are having less sex than they did 25 years ago.

While there was a dip across factors that include genders, race, regions and work statuses, married couples saw the biggest decrease.

The report, which used General Social Survey data taken between 1989 and 2014, discovered that adults are having sex seven to nine times less each year than they did in the 1990s, when they got busy between 60 to 62 times. By 2014, the average number dropped to under 53.

Married or partnered couples having sex dropped from 73 times a year in 1990 to 55 in 2014, while singles have sex 59 times.

There are several reasons for the big chill, the report found. One major factor is a sharp drop in the number of people partnering up. In 2014, 59 percent of American adults were cohabitating, compared to 66 percent in 1986.

While no definite cause for the lack of sex was determined in the study, we can’t discount factors like everyonebeing glued to their smartphones as well as rising levels of depression, less happy people in their 30s and up and side effects from sexual dysfunction medications, The Washington Post reported.

“Are they less happy and thus having less sex or are they having less sex and therefore less happy? It’s probably some of both,” the study’s lead author Jean Twengesaid. “We do know that sexual frequency is linked to marital satisfaction, so overall, if you have fewer people having sex, you could have people who are less happy and less satisfied with that relationship.”

Even that old standby of “Not tonight, honey, I’m tired” is more of a reality than ever.

“I would say the No. 1 cause for a lack of sex is fatigue,” Pepper Schwartz, a University of Washington sociology professor, told the Post, especially with couples “working to create a two-income family to stay middle class or above. People’s minds are occupied with things other than the physical connection.”

So what does Schwartz recommend to light that fire in the bedroom, or wherever you so desire?

“Energy, focus and time and the right mood.”

Sounds like you better take a nap, power down your devices — after you block off time for a steamy sex sesh in your calendar of course — maybe light some candles and get busy, America.