Missouri ranked 17th in population in the US (down from 15th in 1990) with an estimated total of 5,672,579 in 2002, an increase of 1.4% since 2000. Between 1990 and 2000, Missouri's population grew from 5,117,073 to 5,595,211, an increase of 9%. The population is projected to reach 5,718,000 by 2005 and 6.3 million by 2025. The population density in 2000 was 81.2 persons per sq mi.
In 1830, the first year in which Missouri was enumerated as a state, the population was 140,455. Missouri's population just about doubled each decade until 1860, when the growth rate subsided; the population surpassed the 2 million mark at the 1880 census, 3 million in 1900 (when it ranked 5th in the US), and 4 million during the early 1950s.
In 2000, the median age for Missourians was 36.1. In the same year, 25.5% of the population were under age 18 while 13.5% were age 65 or older.
More than half of all Missourians live in urban areas. The largest cities and their estimated 2002 populations are Kansas City, 443,471, and St. Louis, 338,353—both well below the 1980 figures. The St. Louis metropolitan area, embracing parts of Missouri and Illinois, comprised an estimated 2,569,029 people in 1999 while metropolitan Kansas City, in Missouri and Kansas, had a population of 1,755,899.