In armed conflicts, the civilian casualty ratio (also civilian death ratio, civilian-combatant ratio, etc.) is the ratio of civilian casualties to combatant casualties, or total casualties. The measurement can apply either to casualties inflicted by or to a particular belligerent, casualties inflicted in one aspect or arena of a conflict or to casualties in the conflict as a whole. Casualties usually refer to both dead and injured. In some calculations, deaths resulting from famine and epidemics are included. Starting in the 1980s, it was often claimed that 90 percent of the victims of modern wars were civilians, repeated in academic publications as recently as 2014. These claims, though widely believed, are not supported by detailed examination of the evidence, particularly that relating to wars (such as those in former Yugoslavia and in Afghanistan) that are central to the claims. Some of the citations can be traced back to a 1991 monograph from Uppsala University which includes refugees and internally displaced persons as casualties. Other authors cite Ruth Leger Sivard's 1991 monograph in which the author states "In the decade of the 1980s, the proportion of civilian deaths jumped to 74 percent of the total and in 1990 it appears to have been close to 90 percent." The most comprehensive examination of civilian war deaths throughout history is by William Eckhardt, in which Eckhardt states: On the average, half of the deaths caused by war happened to civilians, only some of whom were killed by famine associated with war...The civilian percentage share of war-related deaths remained at about 50% from century to century. (p. 97) Mexican Revolution (1910–20) Although it is estimated that over 1 million people died in the Mexican Revolution, most died from disease and hunger as an indirect result of the war. Combat deaths are generally agreed to have totaled about 250,000. According to Eckhardt, these included 125,000 civilian deaths and 125,000 combatant deaths, creating a civilian-combatant death ratio of 1:1 among combat deaths. World War I 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