But the study's most surprising finding was a sharp drop in sexual activity among couples.
Researchers reckon that the decline in sex from the 90s to now could be down to changes in the way we conduct relationships, - we're less likely to have longterm, steady partners (and those with longterm partners were shown to have more frequent sex) - our likelihood to be living at home in adulthood, and the possibility that we're spending more time on social media instead of with our partners. We couldn't possibly be having less sex than previous generations, could we?
63% of partnered men over age 70 had sex from a few times per month to weekly, while only 15% of married men in that age group boasted the same sexual frequency.
A new study released by the Archives of Sexual Behavior found that USA adults are having less sex than they did during the 1990s, partially due to higher numbers of unpartnered individuals, who tend to have sex less often than their married counterparts.
The average person used to have sex 60 to 62 times a year in the 1990s, but by 2014 that number dropped to less than 53 times per year.
The professor of psychology at San Diego State University wonders, "Are they less happy and thus having less sex or are they having less sex and therefore less happy?"
One factor is the higher percentage now of unpartnered people, who tend to have less sex than partnered ones.
How major USA stock market indexes fared on Friday
However, Yellen said, "I now see no evidence that the Federal Reserve has fallen behind the curve". The Fed has been careful to emphasize that any rate hikes will follow the progress of the economy.
So much for Americans being obsessed with sex.
Regardless of the reasons, it's clear that younger people just aren't having sex as often as their parents and grandparents did at their age.
In the early 2000s, Sherman said, unmarried individuals surpassed married individuals in terms of total sexual frequency.
There's some evidence to suggest that sex frequency can be a be a proxy for happiness, meaning it's a trend public health and policy experts should consider examining. "It's probably some of both", Twenge said in a statement.
"We have a time when people in theory should be happy and satisfied with their lives, based on some social indicators", Twenge said.
There's also the possibility that a hangover from the Great Recession, while not directly contributing to libido, could affect sex rates by taking a toll on marriage. While she and her team describe a decidedly unsexy situation in their report, the numbers don't indicate whether Americans will want to get down with each other any more often, any time soon.
"If you think about the way people spend their time, that's what had the biggest effect on people's lives", Twenge said.