<Tr> <Td> Flag </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Area </Td> <Td> 22,402,200 km2 (8,649,538 sq mi) </Td> <Td> 9,526,468 km2 (3,794,101 sq mi) </Td> </Tr> <Tr> <Td> Population </Td> <Td> 293,047,571 (1991) </Td> <Td> 252,127,402 (1991) </Td> </Tr> <Tr> <Td> Population density </Td> <Td> 13.1 / km2 (33.9 / sq mi) </Td> <Td> 33.7 / km2 (87.4 / sq mi) </Td> </Tr>

When did the united states and the soviet union become allies