https://www.jhunewsletter.com/article/2019/02/why-are-we-having-less-sex-today-than-ever-before

That's from John's Hopkins citing studies by reputable organizations on the matter. There are tons of other articles, papers and studies on the topic.

Basically, even in the most active demographics, about ~40% of people haven't had sex in the last year at any time they ask. The number is greater than 50% before college and the numbers in adults has also seen similar reductions across the board.

Basically, people don't bang anywhere near as much as we all lead each other to believe. Most people you know have had 1 or 0 sexes in the last year. By their own admission. While a much smaller cut of the population has had multiple partners or lots of sexes.