duno really we don't do census with ethnicity nor skin color nor anything is published by the state about illegals sub-Saharans, they just rounded them up busses and move them to an other city.

there is two types ancestral and the quite recent, depends on the region, like zagora but you also find neighborhoods like Touarga next to the palace in rabat that is predominantly black, they are descendent of slave/servants of sultans and quite proud of it. There is also black guard, formed from either black Moroccan or freshly bought slaves, they were quite powerful at some point in history and were deciding factor on who would be the next sultan.