I wouldn’t trust any Nigerian government body that publishes data. For it is the same approach they use in working in the civil service (where they seem to spend more time under the mango tree eating groundnut) that they approach data collection.
The real trustworthy data is with the consumer goods companies and with the telephone companies. Which is why I tend to believe former NPC head Festus Odimegwu who undiplomatically questioned the population count of the North before he was given the boot. He should know for Nigerian Breweries which he headed sells drinks targeted to the masses in every nook and cranny of Nigeria.
But the truth is coming out slowly but surely. Satellite imaging combined with telecommunications subscriber data are revealing rough estimates of Nigeria’s population.