Affiliation: | 1.Demography and Population Studies Programme, Schools of Public Health and Social Sciences, University of the Witwatersrand, Johannesburg, South Africa;2.Demography and Social Statistics Department, Obafemi Awolowo University, Ile-Ife, Nigeria;3.Department of Geography, University of Zambia, Lusaka, Zambia;4.Department of Sociology and Anthropology, University of Uyo, Uyo, Nigeria |