ID=71134352The 10-month-old fight against the Islamic State militants in Iraq and Syria has cost the Pentagon at least $2.74 billion, according to newly released Defense Department data.

On average, that's about $9.1 million daily to cover the costs of flying sorties, dropping bombs, gathering intelligence, maintaining a small network of operating bases, providing logistical support and paying thousands of service members who are supporting the mission in Iraq and across the U.S. Central Command region, according to the data released Thursday.

The Air Force accounts for the bulk of that money, about 67 percent. Navy expenses account for about 16 percent of the war's cost, the Army about 10 percent and Special Operations Command about 7 percent.

The Marine Corps was not listed in the cost data, which covers operations from Aug. 8, 2014, when airstrikes began in Iraq, through May 21.

The cost of operations in Iraq and Syria may rise this summer as the U.S. military deploys an additional 450 troops to Iraq. Roughly 3,000 are there now.

Spending on current operations in Iraq is a small fraction of the money that flowed following the initial 2003 U.S. invasion. The cost of those operations peaked during the "surge" in 2008 at about $389 million daily, or about $142.1 billion that year, according to a report from the National Priorities Project.