From the passage provided, extract the number of casualties by nation during World War II

Context: According to Russian government figures, USSR losses within postwar borders now stand at 26.6 million, including 8 to 9 million due to famine and disease. In August 2009 the Polish Institute of National Remembrance researchers estimated Poland's dead at between 5.6 and 5.8 million. Historian Rüdiger Overmans of the Military History Research Office published a study in 2000 that estimated the German military dead and missing at 5.3 million, including 900,000 men conscripted from outside of Germany's 1937 borders, in Austria, and in east-central Europe. The Red Army claimed responsibility for the majority of Wehrmacht casualties during World War II. The People's Republic of China puts its war dead at 20 million, while the Japanese government puts its casualties due to the war at 3.1 million.

Answer: USSR - 26.6 million
Poland - 5.8 million
Germany - 5.3 million
China - 20 million
Japan - 3.1 million