I always shoot jpeg. I didn't do a first count on the images, but was shooting between 750-1200 per day. I do a lot of in camera deleting while shooting and depending on the sport the keeper rate is a lot higher than others. Generally I would say my keeper is around 90%, of that I would say that they are all good usable images, but again depending on the sport, using figure skating, I would say that keeper rate is around 95%, and 80% are solid images. I may keep a few that are border line in the first edit. I run everything through photoshop, and then go through everything again deleting the ones that don't work. Most of these are the borderline that end up getting dumped.
I use photo mechanic and go through and ID each image, when I originally download the raw files, I add the event and the date, I also get a copy of the game roster so I can add the correct names. For the team sports I copy the roster and add it to folder. Names have to be correct. I don't add any other file info to the images. For the athletes that have numbers, it's easy, for the sports where they don't, judo have names on the back, so I shoot the match board and then their back for the name. For Badminton I shoot the match board with the names, and then just shoot, each player is wearing team colours so that's how I ID those. Any I can't ID by name I just ID by the team.