I'm thinking of the more formalised, 1v1 style jousting rather than the earlier group competitions.

Most obviously - what mortality rate would we expect to see?

More difficult to answer - how many serious injuries would we expect? That would include things like broken bones or what have you.

If they were quite high (which I'd imagine they were, considering the sport consists of two guys in armour trying to knock the other off a galloping horse) - what was the reward like to entice people to take part?