Al Capone's stated "legitimate" income was modest also, but it was only something like one percent of his actual annual take. That's why they eventually got him for income tax evasion.
Of course, the Reverend Al doesn't have to worry about any action from the IRS, for a reason too tiresome to reiterate.
Mr. Obama won’t be in office forever, Al. Might be time to check out some villas in Barbados.