Were West African slaves mostly Muslim?

While many observed indigenous tribal beliefs, it has been estimated that between 7 and 30 percent of African slaves were Muslims. Handwritten verses ... They controlled the overland trading routes that transported oriental goods from the Far East to Europe, ruling from India to Western Africa. read more

At first these slaves traded to the coast were mostly non muslim, how ever towards the end of the slave trade this rule began to collapse. The reason for the slaves being non muslim was religious. The the keeping of slaves was culturally and theologically justified at the time based on interpretations by scholars and imans of the Koran. read more