$250 billion per year for overseas US military

A report estimates that the cost of maintaining the US overseas military presence is about a quarter of a trillion dollars per year:
"The final bill: The United States spends approximately $250 billion annually to maintain troops, equipment, fleets, and bases overseas."

The full report can be found here.

36% (550,000) of all US troops (1.4 million) are based overseas. If we exclude those in Iraq and Afghanistan, about 25% (350,000) are based overseas.