Yes indeed. According to Demographia: "The population estimates in Nigeria are also of concern. The 2006 census results were highly disputed For example, the federal census indicated a population for the state of Lagos of 9.1 million. A parallel census conducted by the state found the population to be 17.5 million. Demographia World Urban Areas bases its population on the federal census, consistent with a policy of relying on the highest legal authorities in cases of conflict. However, it is possible that the population of Lagos (and perhaps other urban areas of Nigeria) is substantially higher than indicated."