If you do a search for Poker Table Ratings you will find a site that tracks cash games. PokerStars
pulled out of allowing them to include their stats back in 2012 but seems to be allowing them again. It used to be a free site but now it's paid/subscription only so you'll need to subscribe to see info on players cash stats.
There also used to be a ban on checking it while signed into a poker client. Not sure if this is still true. Maybe others will have more info on this.