Thanks everyone for the responses. I intend for my WW2 collection to represent the entire world war, not just Europe which is the reason why I want to reflect these demographics accurately. These are some statistics I have found on the British Empire and the USA:
According to this:
http://en.wikipedia.org/wiki/Historical ... .932010.29African Americans made up 9.8% of the US population. Since all men were conscripted would it be accurate to paint 10% of my US troops black?
According to this:
http://www.academia.edu/444982/The_Brit ... o_lecture_The British Empire had 8,252,000 soldiers. India + West Africa + East Africa = 2,165,000 which is 26%. Would this be accurate? I understand that Africa had white people and that the Dominions had blacks/aborigines. But I can't investigate every single case accurately, so some simplification is inevitable, but I still want it to be somewhat precise.
I had no idea about Blacks in the German and Japanese army. Do you have any sources on this topic? I've done some extensive googling but I haven't found anything that suggests that they represented more than 1% of the army. What about the Soviets?
An additional question, I know the US army was segregated until 1948, but I recall that some units were integrated at certain times in battles (such as the Battle of the Bulge) due to white men shortages. How accurate is this?