This.
The biggest slave trading states were the Oyo and Dahomey.
Dummy, Oyo empire was an hinterland Yoruba empire and it wasn't anywhere near the coast, albeit there are other Yoruba subgroups on the coast. And Oyo never really ventured to the coast because it used cavalry (horses) for most of its trading and wars - and due to tsetse fly, in the rain forest around the coast, it was unsafe. Also, Bight of Benin, where Yorubas and Dahomey are located wasn't really a big slave coast, until the late 1700s and 1800s, when Oyo empire had already collapsed, hence when you check all slave records from the 1600s to early 1700s, you wouldn't see that many slaves from the Bight of Benin.
However, Arochukwu Igbos sold millions of other Igbos into slavery in the Bight of Biafra, hence that was biggest slave trade coast in present day Nigeria. And you can check the slave records from 1600s to see how thousands of Igbos have been getting sold into slavery from the 1600s by their Arochukwu brothers.
Don't confuse Oyo with Arochukwu Igbos - two different people. And cacs didn't get to Oyo until the 1800s when it had already collapsed because they were scared of the powerful Yoruba empire in the hinterland. Oyo also protected Yorubas from being enslaved.