* No firm count of contractors in Afghanistan

* Lack of data creates questions about oversight

* U.S. official calls for funding, new regulations

The U.S. government does not know exactly how many contractors it employs in Afghanistan, a U.S. commission said on Monday, raising basic questions about oversight of wartime operations.

Contractors in Afghanistan outnumber U.S. troops there and scandals involving misconduct by employees of private firms on the U.S. payroll in Afghanistan a