The population of Burundi in 2003 was estimated by the United Nations at 6,825,000, which placed it as number 95 in population among the 193 nations of the world. In that year approximately 3% of the population was over 65 years of age, with another 48% of the population under 15 years of age. There were 95 males for every 100 females in the country in 2003. According to the UN, the annual population growth rate for 2000–2005 is 3.10%, with the projected population for the year 2015 at 9,834,000. The population density in 2002 was 240 per sq km (622 per sq mi), making it one of the most densely populated countries in Africa. The density is greatest in north-central Burundi.
It was estimated by the Population Reference Bureau that 9% of the population lived in urban areas in 2001. The capital city, Bujumbura, had a population of 321,000 in that year. Apart from Bujumbura, urban areas are small and serve mainly as commercial and administrative centers. According to the United Nations, the urban population growth rate for 2000–2005 was5.9%.
The prevalence of AIDS/HIV has had a significant impact on the population of Burundi. The United Nations estimated that8.3% of adults between the ages of 15–49 were living with HIV/AIDS in 2001. The AIDS epidemic causes higher death and infant mortality rates, and lowers life expectancy.