Here some World War I casualty figures as a percentage of prewar population from other countries (source: Wikipedia – note ranges given when sources do not agree):

• Serbia: 16.67%-27.78% (750,000-1,250,000 people)
• Ottoman Empire: 13.26%-15.36% (2,825,000-3,271,844 people)
• Romania: 7.73%-8.88% (580,000-665,706 people)
• France: 4.29%-4.39% (1,697,000-1,737,800 people)
• German Empire: 3.39%-4.32% (2,198,420-2,800,720 people)
• Austro-Hungarian Empire : 3.48%-4.05% (1,787,000-2,081,200 people)
• Greece: 3.23%-3.67% (155,000-176,000 people)
• Bulgaria: 3.41% (187,500 people)
• Italy: 2.96%-3.49% (1,052,400-1,243,400 people)
• UK: 1.79%-2.2% (826,746-1,012,075 people)
• Belgium: 1.34%-1.95% (99,416-144,337 people)
• Russian Empire: 1.62%-1.94% (2,840,000-3,394,369 people)
• New Zealand: 1.52%-1.64% (16,711-18,053 people)
• Montenegro: 0.6%-2.67% (3,000-13,325 people)
• Portugal: 1.49% (89,222 people)
• Australia: 1.24%-1.32% (59,330-62,081 people)
• Canada: 0.81%-0.9% (58,639-64,997 people)
• Newfoundland: 0.6%-0.79% (1,204-1,570 people)
• South Africa: 0.12%-0.16% (7,121-9,592 people)
• USA: 0.13% (117,465 people)
• India: 0.02% (64,449-73,895 people)
• Japan: 0.01% (300-4,661 people)

In terms of absolute numbers, both the Russia and the Ottoman Empires fared the worst, with potential deaths of over 3 million apiece and the end of both Empires.

The German and Austro-Hungarian Empires would also cease to exist at the end of the conflict.