I feel like, roughly speaking, the first Atlantic system started off quite small because Native Americans were slave labor starting with Columbus. The second Atlantic system passed Barbary slaving. Import into the US was banned in 1808.
Africans until the early seventeenth century arrived as indentured servants. This occasionally comes up in the lineage of guests on the PBS show Finding Your Roots.
Indentured servants from Europe plus political deportations might have outnumbered Africans. I’ve heard this is true at least in the Caribbean. In my family, our origin could be Scotland or Ireland; both populations were called Irish at the time.
Barbary Slave Trade 1500–1800
https://en.wikipedia.org/wiki/Barbary_slave_trade
Atlantic Slave Trade 1500-1800
https://en.wikipedia.org/wiki/Atlantic_slave_trade
Abolition of Slavery from Britain 1807 and 1833
The Abolition of Slavery in Britain happened in 1807 making illegal to purchase slaves from Africa and then in 1833 stopping slavery in the Caribbean. https://www.historic-uk.com/HistoryUK/HistoryofBritain/Aboli...