About 5% are acceptable to you which is about what a good photographer would expect? Bernard would you normally take this many at an event? When I do events - which I do a lot - then about 300 would be my maximum. 5% is about what I would be happy to get.
Well, I love this thing, but it really isn't my cup of tea. I shoot 95% of my images from the top of a tripod using live view, so I first had to remember how to activate the AF of my body. :-)
Some of the images were fairly easy because movements were slow, but some of it is pretty challenging because of the sheer speed of the action together with my attempts to keep a sense of movement when needed.
Since I bought 32GB cards a few years ago I have sort of stopped defining limits to the amount of images I don't want to shoot during a session. I had not anticipated I would shoot so many on Sunday, but as the event unfolded, between the speed of movement, the very quickly changing harsh light (there was one big spot only), the sheer amount of interesting action,... I realized I was shooting quite a lot.
Anyway, I am sure that you would have done much better in similar circumstances.
Cheers,
Bernard