20% of men get 80% of the women
People apply the Pareto principle to everything as a means to try and explain it. Taxes, voting, shopping, drunk driving, dating, wealth distribution.
It would be far more accurate to say something like "a minority population of men have been both genetically and socially lucky enough to have traits that are immediately desired by women leading to their ability to have multiple sex partners. Especially with birth control, abortion, morning after pills, the consequences to having multiple partners have less meaning allowing for greater occurrence."
Saying "20% of men get 80% of the women" makes it kinda sound like women are enslaved to the men, or like no other man can fulfill them, when really a one night stand, once in her life, at a party 20 years ago with some guy because he had a ferrari, or was famous, or was "really hot," counts towards the statistic.
But it's really meaningless in the scope of their life and eventual mating.