WildBill has a very true & accurate post, his insight is always stout, but just as I've said before, sharps come in all sizes, shapes, and colors..and the answer doesn't have an median number.
It is relative to how sharp one is, how much in the know one is, what size bankroll, shopping options available, one's MO(gambler or grinder),etc..many variables.
Besides after a certain point, the best sharps have to almost become a "Bookmaker's bookmaker", or hire an army of people, or go in bed with stick-up artists, or go Offshore as an start-up Book..to be able to impale enough mullets to make it relative for them any longer.