And yet... The examples mentioned and the justifications for big errors/fakes in many countries (that historically have been highlighted for scares around overpopulation) are very plausible. "Most countries run census" is not the same as "most countries run mostly reliable census" or "most of the world population is covered by a reliable census".

Aren't there plenty of incentives for over expressing population numbers in many countries, specially in underdeveloped ones?