It's hard to say, but each of us thinks it's 70-80% of the hands. After analyzing my hand history, it turned out to be about 20%. It seems to me that it is because of our selective memory, where we do not remember how many hands we managed to win with gag, but we remember every "bad beat" because this is a variation that, from our point of view, shouldn't have happened. That why we think that most of our hands lose in the river