I am 36, or nine, as I have only had nine birthdays...
And Eman means that if a couple have sex three times a week for the first ten years, and two times thereafter, a couple married when they were twenty would have had sex ((52*3*10)+(52*2*20) 3640 times, whereas the young couple in their mid twenties would only have had sex (52*3*5) 780 times. Obviously the weekly figures varies (glad to say), but the maths means that that wrinkly old couple have probably made the beast with two backs five times as often as the lissom twenty-somethings.
Thus your parents have had more sex than you.
People living in glass paradigms shouldn't throw stones...