Healthcare costs for the military have skyrocketed over the last decade with the United States embroiled in two wars, and recent figures from the Department of Veterans Affairs (VA) reveals costs related to disability benefits have also seen a sharp increase. Since 2000, the amount the U.S. has paid to disabled vets has risen from about $14.8 billion to $39.4 billion, USA Today reports.

The reason for the sharp increase over the last 12 years has a lot to do with the repeat deployments, experts say. Starting in 2000, disabled veterans made up about 9 percent of the total population of former service​members, but by 2011 that figure had jumped to about 15 percent, a statistic indicative of the ongoing toll of the wars in Iraq and Afghanistan.

“I would point first and foremost to multiple deployments,” Allison Hickey, a retired Air Force brigadier general and the VA undersecretary for benefits, told the publication. “I would call it unprecedented demand.”

The significant number of injuries from Iraq and Afghanistan is certainly a large contributing factor. According to the Armed Forces​ Surveillance Center, between October 2001 and June 2012, more than 891,900 troops were hospitalized.