As for a 9:10 ratio, it all depends on the rate of committed relationships. Remember that this is all people, married, committed, and single. If they're all single, 9:10 is probably pretty good. If 95% of people are in a committed relationship (ignoring homosexuality, which probably cancels out) then you have no hope at all. If we pick a more sane number like, say, 75% (not sure how sane, but...) then that results in about the singles scene having about a 2:3 ratio, which is not so great for the people on the 3 side.