FACTBOX: The Iraq war's costs in dollars

(Reuters) - Congress on Tuesday and Wednesday is receiving reports on the state of war in Iraq from the U.S. commander on the ground, Gen. David Petraeus, and Washington's ambassador to Baghdad, Ryan Crocker.

Following are some facts about the financial costs of the Iraq war.

* Since the September 11 attacks on the United States, Congress has approved $691 billion to pay for wars in Afghanistan and Iraq and such related activities as Iraq reconstruction, the Congressional Budget Office said in January. Of the total, the CBO estimated $440 billion had been spent on the Iraq war.

* The two wars could cost taxpayers a total of $2.4 trillion by 2017, when counting interest costs, because combat is being financed with borrowed money, according to a study issued by the CBO, a nonpartisan budget analyst for Congress. The CBO estimated that of the $2.4 trillion long-term price tag, about $1.9 trillion would be spent on Iraq.

* A long-term U.S. military presence in Iraq would cost around $10 billion to $25 billion a year, depending on how often troops are engaged in combat, the CBO said in September 2007. CBO based its estimates on a 55,000-troop presence in Iraq; there are approximately 158,000 U.S. troops now there.

* The estimated cost of boosting Iraq's oil output to 6 million barrels per day had soared to as high as $75 billion, a government adviser said in June 2007, when Iraq's shattered oil industry was producing around 2 million bpd. Officials had said around $25 billion would be needed to triple that figure.

(Writing by Paul Grant, Washington Editorial Reference Unit, editing by Patricia Zengerle)