I think we will have more accurate result about this from this
Chainanalysis report which also include the information provided above.

We may be leading in p2p but adoption? Hell No!!!
According to the report which is also indicated in the image above, did you actually know that Kenya is ranked higher even in P2P trading than Nigeria? Kenya is even ranked as the first.
Kenya ranked 1
Vietnam ranked 3
Nigeria ranked 18
On-chain cryptocurrency value received, weighted by purchasing power parity (PPP) per capita
On-chain retail value transferred, weighted by PPP per capita
Peer-to-peer (P2P) exchange trade volume, weighted by PPP per capita and number of internet users
Why using PPP? While not nominal? Nominal would have given us the information we need which makes Nigeria number in Africa in P2P trading and probably in adoption. Or maybe there is something I am not still getting rightly about this but using purchasing power in the calculation makes this not to be accurate to me, but although it was indicated that PPP was used for the three calculations which were used for the crypto adoption index.