“…Since at least 80% of those captured by the Muslim slave traders were calculated to have died before reaching the slave markets, it is believed that the death toll from 14 hundred years of Arab – Muslim slave raids into Africa could have been as high as 112 million.”

John Azumah holds a PhD in Islamics from the University of Birmingham, UK, and is the Director for the Centre of Islamic Studies at the London School of Theology. He has previously served as a Research Fellow with the Akrofi-Christaller Institute in Ghana. Dr. Azumah is the author of The Legacy of Arab-Islam in Africa: A Quest for Inter-Religious Dialogue (Oxford: Oneworld Publications, 2001) and has written articles on the subject in various academic journals.

https://books.google.co.jp/books/about/The_legacy_of_Arab_Islam_in_Africa.html?id=pSoQAQAAIAAJ&redir_esc=y

Note: The following quotes were transcribed from statements Azumah makes in the video below (they did not come from his book):

“A comparison of the Islamic slave trade to the American slave trade reveals some extremely interesting contrasts.

While two out of every three slaves shipped across the Atlantic were men, the porportions were reversed in the Islamic slave trade.  Two women for every man were enslaved by the Muslims.

While the mortality rate of the slaves being transported across the Atlantic  was as high as 10%, the percentage of the slaves dying in transit in the Tran Saharan and East African slave market was a staggering 80 to 90%.

While almost all the slaves shipped across the Atlantic were for agricultural work, most of the slaves destined for the Muslim Middle East were for sexual exploitation as concubines in harems and for military service.

While many children were born to the slaves in the Americas, the millions of descendants are citizens in Brazil and the United States, very few descendants of the slaves who ended up in the Middle East survived.

While most slaves who went to the Americas could marry and have families, most of the male slaves destined for the Middle East were castrated and most of the children born to the women were killed at birth.

It is estimated that as many as 11 million Africans were transported across the Atlantic, 95% of which went to South and Central America, mainly to Portuguese,  Spanish, and French possessions, only 5% of the slaves ended up in what we call the United States today.

However, a minimum of 28 million Africans were enslaved in the Muslim Middle East.  Since at least 80% of those captured by the Muslim slave traders were calculated to have died before reaching the slave markets, it is believed that the death toll from 14 hundred years of Arab – Muslim slave raids into Africa could have been as high as 112 million.

— Dr. John Azumah

Slavery continues in the Islamic world. Because it is religiously sanctioned, many Muslims, including some who come to live and work in the West, continue the practice.

https://adarapress.com/2016/08/26/texas-judge-orlando-garcia-bans-muslim-couple-from-united-states-why-not-prison/