The death of a high-ranking U.S. Army officer, Maj. Gen. Harold J. Greene, at a military training facility in Kabul on Tuesday was the latest blow in a long line of failures for the Afghan military and underlined the susceptibility of the U.S.-Afghan partnership to extremism. In all, there have been 2,202 deaths of U.S. soldiers in Afghanistan since the U.S.-led Operation Enduring Freedom began in 2001, according to the U.S. Department of Defense

Greene’s death is a reminder that the ongoing coalition operations in Afghanistan have not always gone according to plan. Of those killed in Afghanistan, 1,820 died from combat, and 382 died in non-hostile situations.

The deadliest year for U.S. troops in Afghanistan was 2010. Some 499 soldiers were killed in Afghanistan that year, followed by 418 deaths in 2011. The majority of soldiers who have died during Operation Enduring Freedom were between 21 and 26 years of age.

An additional 19,797 U.S. soldiers have been injured in Afghanistan as of Wednesday, the Department of Defense reports.