Laos' population was estimated at 6.5 million in 2012, dispersed unevenly across the country. Most people live in valleys of the Mekong River and its tributaries. Vientiane prefecture, the capital and largest city, had about 740,010 residents in 2008. The country's population density was 27/km2
According to the 2010 Revision of the UN World Population Prospects,[2] the population of Laos increased from 1.7 million in 1950 to 6.2 million in 2010. Until the year 2000 the proportion of children 0–14 years of age was over 40% of the total population. Due to decreasing fertility rates this proportion decreased to 34.5% in 2010. The proportion of elderly people is still very low (3.9%), although the proportion doubled between 1950 and 2010