In 1807 Britain, which held extensive, although mainly coastal, colonial territories on the African continent (including southern Africa), made the international slave trade illegal, as did the United States in 1808.In Senegambia, between 13, close to one-third of the population was enslaved.
In early Islamic states of the Western Sudan, including Ghana (750–1076), Mali (1235–1645), Segou (1712–1861), and Songhai (1275–1591), about a third of the population was enslaved.
In Sierra Leone in the 19th century about half of the population consisted of slaves.
Quote: "The African continent was bled of its human resources via all possible routes.
Across the Sahara, through the Red Sea, from the Indian Ocean ports and across the Atlantic.
At least ten centuries of slavery for the benefit of the Muslim countries (from the ninth to the nineteenth)." He continues: "Four million slaves exported via the Red Sea, another four million through the Swahili ports of the Indian Ocean, perhaps as many as nine million along the trans-Saharan caravan route, and eleven to twenty million (depending on the author) across the Atlantic Ocean" To overdraw its evils is a simple impossibility....
We passed a slave woman shot or stabbed through the body and lying on the path.
The population of the Kanem was about a third slave. Between 17 from one- to two-thirds of the entire population of the Fulani jihad states consisted of slaves.
The population of the Sokoto caliphate formed by Hausas in northern Nigeria and Cameroon was half-slave in the 19th century.
It is estimated that up to 90% of the population of Arab-Swahili Zanzibar was enslaved.
Roughly half the population of Madagascar was enslaved.
Slavery was known in the very first civilizations such as Sumer in Mesopotamia which dates back as far as 3500 BC, as well as in almost every other civilization.