Arizona's population growth rate has been one of the nation's highest for two decades.
The state ranked 19th in population in the US with an estimated total of 5,456,453 in 2002, an increase of 6.4 % since 2000. Between 1990 and 2000, Arizona's population grew from 3,665,228 to 5,130,632, the 5th-largest increase and 2nd-largest percentage gain (40%) among the 50 states. The population is projected to reach 6.4 million by 2025.
Despite its rapid population growth, the state still had a population density of only 45.2 persons per sq mi in 2000. The median age was 34.2. Arizonans 65 years of age or older comprised 13% of the population in 2000, while persons under 18 years old accounted for 26.6%.
Three out of four Arizonans live in urban areas. The largest metropolitan areas are Phoenix-Mesa, with a 1999 estimated population of 3,013,696, and Tucson, with an estimated 803,618. The largest cities proper are Glendale, with a 2002 estimated population of 230,564; Scottsdale, 215,779; and Tempe, 159,508. More than half the state's population resides in Maricopa County, which includes every leading city except Tucson. Phoenix was the nation's sixth-largest city in 2002.