I would say 25-30% depending in who your using. Ermac for instance has a pretty easy 41% combo BnB but getting the opponent to get hit by it is harder.
I'm using kabal as my main so about 25% for my BnB.
but yeah good to hear its around there
Was hitting jades combos fairly easy getting those #s then I messed with another character - for some reason i can't remember to save my life - hit combos above that amount.