Data are mid-year estimates. Since 1999 (as of December, 31) balance of population is based on the results of 2002 National Population Census. For years 1989 to 1999 (as of June, 30) data based on estimates method. Prior to 1989, adjustments in the population series associated with census years (1988, 1978 and 1970), result in statistical discrepancies in the sum of components of change in population