World War I casualties
The total number of military and civilian casualties in World War I were about 40 million: estimates range from 15 to 19 million deaths and about 23 million wounded military personnel, ranking it among the deadliest conflicts in human history.
Serbian Campaign of World War I
The Serbian Army declined severely towards the end of the war, falling from about 420,000 at its peak to about 100,000 at the moment of liberation. The estimates of casualties are various: the Serb sources claim that The Kingdom of Serbia lost more than 1,200,000 inhabitants during the war (both army and civilian losses), which represented over 29% of its overall population and 60% of its male population, while western historians put the number either at 45,000 military deaths and 650,000 civilian deaths or 127,355 military deaths and 82,000 civilian deaths. According to estimates prepared by the Yugoslav government in 1924, Serbia lost 265,164 soldiers, or 25% of all mobilized people. By comparison, France lost 16.8%, Germany 15.4%, Russia 11.5%, and Italy 10.3%.