What percentage of small businesses earn enough to be taxed more under Obama's plan than they are taxed now?

In business it's easy to have a gross income over $250K. Of course after salaries, utilitieis, inventory, consumables, and all other expenses there may not be enough left to pay the kind of taxes Obama wants to levy. BTW - Obama's income level keeps going down. First it was $250K, then $200K, then $150K, and now it's down to $120K.