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.
Serbian Campaign of World War I
Before the war, the Kingdom of Serbia had 4,500,000 inhabitants. According to the New York Times, 150,000 people are estimated to have died in 1915 alone during the worst typhus epidemic in world history. With the aid of the American Red Cross and 44 foreign governments, the outbreak was brought under control by the end of the year. The number of civilian deaths is estimated by some sources at 650,000, primarily due to the typhus outbreak and famine, but also direct clashes with the occupiers. Serbia's casualties accounted for 8% of the total Allied military deaths. 58% of the regular Serbian Army (420,000 strong) perished during the conflict. According to the Serb sources, the total number of casualties is placed around 1,000,000: 25% of Serbia's prewar size, and an absolute majority (57%) of its overall male population. "L.A. Times" and "N.Y. Times" also cited early Serbian sources which claimed over 1,000,000 victims in their respective articles. Modern western and non-Serb historians put the casualties number either at 45,000 military deaths and 650,000 civilian deaths or 127,355 military deaths and 82,000 civilian deaths.