I did a very basic search for racial demographics of Sweden, the US and Brazil (since someone else mentioned it), then calculated the Shannon diversity index (lower essentially meaning less diversity) and the Pielou evenness (a number between 0 and 1 - higher means less size variation among groups). I didn't find great numbers to work with in the few minutes that I looked. I used these:

US: http://en.wikipedia.org/wiki/Demographics_of_the_United_Stat...

Brazil: http://www.indexmundi.com/brazil/demographics_profile.html

Sweden: http://www.populstat.info/Europe/swedeng.htm

And got:

US:

With Hispanic/non-hispanic breakdown

Shannon: 1.258355 Pielou: 0.5064

Without breakdown

Shannon: 0.9705 Pielou: 0.4987

Sweden:

Shannon: 0.4498 Pielou: 0.2795

Brazil:

Shannon: 0.9509 Pielou: 0.5908

So in terms of diversity, US >= Brazil > Sweden.