What is the avg miles/year on used bikes?

And how many miles can you get out of a bike?

This is all obviously very variable depending on the type of engine as well as how well the previous owner took care of their bike. But I am in the market for my first bike and then mainly looking at used options. A lot of the ones I am seeing have upwards to 24,000 miles on them and I'm not sure if that is a ton for a motorcycle considering I've never had one