I find the ones I consider "keepers" are about 5% and the ones I consider really good way less than 1%. I think some of that is natural. I find that I take photos from different perspectives, different focal lengths, different exposures just continuing to experiment and see if there is an angle. For example I had circled around Notre Dame several times before I saw this differnt angle of the cross, which I really like. But dozens if not hundreds as I experimented.