Depends. If I am doing my documentary work, usually 4-6 keepers, because I shoot each picture a few times in case I shake the camera. I always feel unsteady handholding, though my actual results show few blurred pics, I do it for insurance. Easier than reshooting later.
If I am doing street type work, usually more since each pic can be shot only once, there are a lot more potential images to choose from on a roll. Maybe 10-15 I'll choose if I had a good day.
I read that back in the days of film, Sports Illustrated shot over 100,000 frames and chose about 20 for the swimsuit issue they do every year. That's common in editorial work, I've been told. National Geographic had similarly extreme amounts of film shot for each story and only needed a 10-20 for a story! My low keep rate is quite high by those standards!