(which is sometimes considered part of World War II, or as overlapping). Most of the others involved China or neighboring peoples. The death toll of World War II, being over 60 million, surpasses all other war-death-tolls. On military personnel Military personnel subject to combat in war often suffer mental and physical injuries, including depression, posttraumatic stress disorder, disease, injury, and death. Swank and Marchand's World War II study found that after sixty days of continuous combat, 98% of all surviving military personnel will become psychiatric casualties. Psychiatric casualties manifest themselves in fatigue cases, confusional states, conversion hysteria, anxiety, obsessional and compulsive states, and character disorders. Additionally, it has been estimated anywhere from 18% to 54% of Vietnam war veterans suffered from posttraumatic stress disorder. Based on 1860 census figures, 8% of all white American males aged 13 to 43 died in the American Civil War, including about 6% in the North and approximately 18% in the South. The war remains the deadliest conflict in American history, resulting in the deaths of 620,000 military personnel. United States military casualties of war since 1775 have totaled over two million. Of the 60 million European military personnel who were mobilized in World War I, 8 million were killed, 7 million were permanently disabled, and 15 million were seriously injured. During Napoleon's retreat from Moscow, more French military personnel died of typhus than were killed by the Russians. Of the 450,000 soldiers who crossed the Neman on 25 June 1812, less than 40,000 returned. More military personnel were killed from 1500 to 1914 by typhus than from military action. In addition, if it were not for modern medical advances there would be thousands more dead from disease and infection. For instance, during the Seven Years' War, the Royal Navy reported it conscripted 184,899 sailors, of whom 133,708 (72%) died of disease or were 'missing'. It is estimated that between 1985 and 1994, 378,000 people per year died due to war. On civilians Most wars have resulted in significant loss of life, along with destruction of infrastructure and resources (which may lead to famine, disease, and death in the civilian population). During the Thirty Years' War in Europe, the population of the Holy Roman Empire was reduced by 15 to 40 percent. Civilians in war zones may also be subject to war atrocities such as genocide, while survivors may suffer the psychological aftereffects of witnessing