it depends on what i'm shooting, and what defines 'keepers' (different keepers in different situations).
shooting rugby league, i'll have a high percentage of shots in focus and of the subject desired. but i'll generally whittle it down to the best shots that i feel i can sell - and that will depend on the age of the players.
baseball is the only sport where i use 'burst' mode - to try to get the timing of the batter or the action of the pitcher. i need more practice so my keeper percentage isn't the greatest. shooting cricket, on the otherhand is more predictable.
shooting portraits - generally everything will be in focus and exposed properly, but people usually only choose 1 or 2 poses.
street photography and photos of my daughter can be hit and miss bacuse i'm using a large aperture so a shallow depth of field, and the subject is always moving.
my last trip to Tokyo, i went to
DisneySea where i shot 582 shots on the day. there were 37 images which were taken in the evening of something else so there were a total of 545 photos taken. in my gallery i have 409 images posted. there may be a few in there that aren't the best - but there were some similar shots which i didn't include so it's a wash. whoa, so that's exactly 75% keepers published to web on that trip. if i were sending a .pdf to have a book printed with the shots, i'd try to choose 40.