Civilian casualty ratio
Some 7 million combatants on both sides are estimated to have died during World War I, along with an estimated 10 million non-combatants, including 6.6 million civilians. The civilian casualty ratio in this estimate would be about 59%. Boris Urlanis notes a lack of data on civilian losses in the Ottoman Empire, but estimates 8.6 million military killed and dead and 6 million civilians killed and dead in the other warring countries. The civilian casualty ratio in this estimate would be about 42%. Most of the civilian fatalities were due to famine, typhus, or Spanish flu rather than combat action. The relatively low ratio of civilian casualties in this war is due to the fact that the front lines on the main battlefront, the Western Front, were static for most of the war, so that civilians were able to avoid the combat zones.
The March (1945)
The total number of US POWs in Germany was in the region of 93,000-94,000 and official sources claim that 1,121 died. The British Commonwealth total was close to 180,000 and while no accurate records exist, if a similar casualty rate is assumed, the number who died would be around 2,200. Therefore, according to a report by the US Department of Veterans' Affairs, almost 3,500 US and Commonwealth POWs died as a result of the marches. It is possible that some of these deaths occurred before the death marches, but the marches would have claimed the vast majority.