Guys I'd day one or two, maybe 3-5 in a good year.
Just take 10% of their mounts earnings(its a very good rough estimate) and then deduct 25% of that. The agents are employees of the jocks and thats the usual cut.
So a jock has to have his mounts earn about 13.5 million to clear a mill(1, 350,000 dollars million minus 307,500 dollars to agent).

You guys are way off, maybe 4-5 riders will make that this year.