Pennsylvania ranked 6th in population in the US with an estimated total of 12,335,091 in 2002, an increase of 0.4% since 2000. Between 1990 and 2000, Pennsylvania's population grew from 11,881,643 to 12,281,054, an increase of 3.4%. The population is projected to reach 12.7 million by 2025.
As recently as 1940, Pennsylvania was the 2nd most populous state in the US. By the 1980 census, however, the state had slipped to 4th place, with a population of 11,863,895; it dropped to 5th place in 1990 with a population of 11,881,643.
In 2000, the median age for Pennsylvanians was 38. In the same year, 23.8% of the populace was under age 18 while 15.6% were age 65 or older. The population density in 2000 was 274 persons per sq mi.
The largest city in the state, Philadelphia, was the 5th-largest US city as of 2002, with a population of 1,492,231. Philadelphia's population has declined since 1970, when 1,949,996 people lived there. The population of its metropolitan area also declined during the 1970s, but then increased from 4,716,559 in 1980 to 4,922,257 in 1990 and stood at an estimated 4,949,867 in 1999. Further, the larger Philadelphia–Wilmington (Del.)–Trenton (N. J.) consolidated metropolitan area increased from 5,680,509 in 1980 to an estimated 5,999,034 in 1999. Pittsburgh's population declined from 616,806 in 1950 to an estimated 327,898 in 2002 in the city proper, and the Pittsburgh metropolitan area population decreased from 2,348,000 in 1970 to 2,331,336 in 1999.
The 2002 estimated populations of Pennsylvania's other major cities were Allentown, 106,105, and Erie, 102,122. Other cities with large populations include Reading, Scranton, Bethlehem, Lancaster, Harrisburg, Altoona, and Wilkes-Barre.