Size matters.
USA has 13% blacks.
Europe...may be 2%. I have done extensive travels in Europe. From Sweden, France, England, Portugal, Spain, Italy, Monaco, Greece. Most blacks I saw were in France. Very few anywhere else.
I’ll take your word for it.
The problem in both situations is the low birthrate for whites; if not for the Welfare Reform of 1996, this country would be 20%+ black (it brought their birthrate down close to whites by ending “more cash for more kids”). One need only look at the explosion of the Hispanic population to see how much difference the low white birthrate makes; they were projected to surpass blacks in numbers by 2020, but after the 2010 census it appeared that it already happened. Granted, they are constantly reinforced by immigration, but they have more pressing need to breed (both welfare AND anchor babies to remain).