Um, I don't know if that is even vaguely calculate-able.
What is a contributed raked hand? Is it any hand that you put any money in, that gets raked? What limits does it work at?
Say you play $10 NL and limp in for 10c and then fold the flop. If that counts as a contributed raked hand, then you'll be getting way way more than 100% rakeback.
I'm going to have to look into this one. I haven't played any Prima in ages because their bonuses went in the toilet....