The combat in Afghanistan and Iraq has shown that military medicine has continued to improve, as it has for most of the last century. Of the 1,077 troops wounded in Afghanistan and Iraq, only 1.6 percent have died of their wounds. This compares to 3.68 percent during the Vietnam war. The improvement is largely because of improved medical technology, especially in the ability to quickly stop bleeding. But the major factor is, as it has been for several generations, the speed with which wounded troops are moved to hospitals. In Afghanistan and Iraq, medical evacuation ("medevac") helicopters stand ready around the clock. Moreover, the medevac crews often contain "trauma teams" of medical specialists who can stabilize badly wounded soldiers. Moreover, the air force has improved the medical facilities on its patient transport aircraft, allowing badly wounded troops to be quickly moved to better equipped facilities in Europe and the United States. All of this is known by the troops, who find the "98 percent odds of surviving a wound" good for morale.