What was the population of Britain and the USA (respectively) in 1939?
The population of Britain in 1939 was estimated as a result of the National Registration Act as 47.96 million. The 1940 census in the USA established the population of that country as 132.16 million so the population would have been within 1% below that number in 1939 given there was only a 7% increase in poulation over the 1939 census.