There is no information on fertility or mortality representative of numbers of Nigerian people. Vital statistics are registered in Lagos but are not representative of the country. The first census was taken in 1952-53 but contained no information of fertility and mortality. The 1962 census was invalidated. The political confusion surrounding the 1963 census will probably invalidate it. Nigeria is the most populous country in Africa. The 1963 census of 56 million is an overestimate, but is much larger than the other countries. According to UN estimates based on the 1953 census, the gross reproduction rate was 3.7 and the crude birth rate between 53 and 57. Age data for boys is recorded systematically as lower than those of girls of the same real age until age 15. Slower physical development and the desire to avoid taxation may account for the discrepancies. Certain tribes tend to conceal their number of children, particularly the first born. Among Moslems it is impossible to check the number of married women who are in "purdah." Migration from and to areas of Nigeria probably affected the young adult male and was not reported. The area of highest fertility was estimated to be in Western Nigeria, particularly in the Yoruba region. The eastern region includes one low-fertility area, Cameroons Province, with a gross reproduction rate under 3. - See more at: http://www.popline.org/node/515936#sthash.TLo2kXkl.dpuf