>>17809599 (OP)This view depends on whether or not you solely count North American whites. If we look at the numbers of slaves traded to the New World, it's generally about 5 million each to both the Caribbean and to Latin America around 500,000 to North America, yet the Black population in the United States dwarfs the population of "Black" Brazilians and that of Afro-Caribbean with both population totaling around 20 million each compared to 44 million African Americans.
Why is this? A combination of racial dynamics, demographics, and identity politics.
Due to the ban on importation of Black slaves in North America, and the distance and cost of sailing from Africa, a slaves life was comparatively valuable, so their relative safety and reproduction was essential for the economy of the South. African Americans populations exploded along with the rest of the USA's. This along with laws against miscegenation, the one drop rule, makes African Americans a visible minority to this day.
While is other parts of a slaves live was practically worthless due to the cost of sailing from Africa being relatively cheap, so it was easier to work a slave to death and have them replaced by fresh arrivals. This along with the intensity of sugar cane harvesting, tropical diseases, made life hell for slaves Caribbean and Brazil. This depressed their birthrates and when combined with less laws against mixing, and European immigration, wiped out a lot of African ancestry across the region compared to the population size.
Black is much wider label in North America, than in South America, where they almost have a reverse one drop rule. People that would hesitate to call themselves Black in the USA due to colorism/racism associated with Black features could get labeled Black instantly in the US, such as Dominicans, Pardo Brazilians, and Upper class mulatto Haitians.