What countries exported the most slaves to America?

At the height of the slave trade, Africa did not have nationalistic countries as we think of them, today. There were large areas of the continent that were controlled by particular tribes. Originally, most of the slaves came from West Africa, but as the practice spread, West African Tribes began enslaving East Africans and transporting them to the Gold Coast. Eventually, even the slave ships ventured to the eastern coast of Africa, and traded in slave to India and the Middle East as well.