The first Africans forced to work in the New World left from Europe at the beginning of the sixteenth century, not from Africa. The first slave voyage direct from Africa to the Americas probably sailed in 1526.
The volume of slaves carried off from Africa reached thirty thousand per year in the 1690s and eighty-five thousand per year a century later. More than eight out of ten Africans forced into the slave trade made their journeys in the century and a half