As in Finland, just 100 years ago. Only 4 months long, but they killed off about 1% of Finland's population. During the four years of the American Civil War, we managed about 2%- but that was years.
And in Finland, only about one death in 4 was a combat casualty. The others were prisoners shot or bayonetted as god practice for the new rookie youngsters as yet accustomed to the realities of their new jobs, those who died under interrogation, or those wounded or frozen- or who were left to starve to death.
[Note, however, the ribbons at their collars and jacket fronts. Those are for the German Iron Cross, First Class, likely associating the young Finnish riflemen with the 4000 volunteers with the 276th Jaegers. And I doubt they got their Iron Crosses for writing real good book reports.]