Probably kinda hard to come up with an accurate percentage. It might vary from country to country.
One way to get an idea, is to have
pokerstars give us some stats as to how many players are in the positive vs negative. The percentage of positive players is probably close to a national average. PokerStars deals billions of
hands per year. Their stats should be pretty close.
I wouldn't be surprised if the percentage of winning players is somehow relative to the percentage of face cards and aces in the deck compared to all other cards.
Aces = 7.6% - Professionals who play poker for a living
Face Cards = 23% Winning players who don't earn enough to play for a living
6 - 10 = 38% - Players who break even or have moderate losses
2- 5 = 30% - Players who consistently lose with occasional wins