The population of Iraq in 2003 was estimated by the United Nations at 25,175,000, which placed it as number 42 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 47% of the population under 15 years of age. There were 103 males for every 100 females in the country in 2003. According to the UN, the annual population growth rate for 2000–2005 is 2.68%, with the projected population for the year 2015 at 34,226,000. The population density in 2002 was 54 per sq km (139 per sq mi). Mesopotamia is the most densely populated region.
It was estimated by the Population Reference Bureau that 77% of the population lived in urban areas in 2001. The capital city, Baghdad, had a population of 4,689,000 in that year. Other major cities included Arbil, 2,368,000, and Mosul, 1,034,000. According to the United Nations, the urban population growth rate for 2000–2005 was 3.3%.