Data are mid-year estimates obtained by averaging official estimates at 31 December for two consecutive years. Data up to 1981 have been aligned to the 1982 census results. Data from 1982 to 1989 have been aligned to the 1990 census results. Data from 1990 to 1998 have been aligned to the 1999 census results. The last population census took place in 1999. From 2006 onwards , census are annual. and cover only part of the population each year. Data from 2000 to 2005 are aligned to the 1st January 2006 census. At the end of each year N, the 1st January census results of year N-2 are available and final. Data for N-1 and N are revised and provisional. Estimates are done with number of deaths and births as well as net migration.