I submit the large black population of the US compared to the non existent black population of other slave destinations that received 10x as many - exactly, spot on Simon.
I was in two minds about bringing this up but I will now.
The Arabs bought black slaves, and it happened for a much longer time than the Trans-Atlantic Slave Trade.
The Trans-Saharan Slave Trade started before the Islamic prophet Muhammad was born and ended in 1962 (that was the year that Saudi Arabia and Yemen bowed to international pressure and finally stopped slavery).
And yet, the Caribbean, the US and Brazil have full-blooded black people, the descendants of slaves, ... but Saudi and other Arab countries don't have full-blooded black people as a proportion of their current population.
^^^ Why is this? ^^^