The population of Cambodia in 2003 was estimated by the United Nations at 14,144,000, which placed it as number 62 in population among the 193 nations of the world. In that year approximately 4% of the population was over 65 years of age, with another 43% 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 2.40%, with the projected population for the year 2015 at 18,421,000. The population density in 2002 was 68 per sq km (176 per sq mi).
It was estimated by the Population Reference Bureau that 16% of the population lived in urban areas in 2001. The capital city, Phnom Penh, had a population of 938,000 in that year. According to the United Nations, the urban population growth rate for 2000–2005 was 4.2%. A great majority of the people live in rural areas, with 90% of the rural population living in the plains of the central third of the country.
Estimates of Cambodia's population vary with the assessment of the impact of the 1970–75 war and the millions killed in its tumultuous aftermath. At the war's end, in April 1975, the population of the capital, Phnom Penh, had swollen to nearly 3 million because of a mass influx of refugees. The new government immediately embarked on a forced evacuation of all urban areas, and by March 1976, only 100,000–200,000 were thought to remain in Phnom Penh. After the installation of the PRK in 1979, the population of Phnom Penh began to increase. Other cities include Batdambang, Kampong Cham, Kampot, Siemreab, Kampong Saom, and Kracheh.