More than 2,400 U.S. troops have died in the Afghan War since 2001. The deadliest year was 2010, with 499 American casualties and a total coalition loss of 711 lives. According to the United Nations, tens of thousands of Afghan civilians have also been killed since the war began. The first six months of 2018 were the deadliest since 2009, when the U.N. started keeping record of civilian casualties, with 1,692 deaths