Primarily an agricultural state through the first half of the 20th century, Oklahoma has assumed a broader economic structure since the 1950s. Manufacturing heads the list of growth sectors, followed by wholesale and retail trade, services, finance, insurance, and real estate. Oil and gas extraction continues to play a major role. The oil industry boomed from the mid-1970s through the mid-1980s. In 1985, however, the boom ended. Prices dropped from $27 a barrel to $13 a barrel within a month in 1985. In 1998, gas and oil production was valued at only $3.4 billion; one-third of what it was worth in the mid-1980s. Oklahoma's unemployment rate, which averaged about 3% in the early 1980s, jumped to 9% in 1983, and then fell to 7% in 1985, and rose again, to 8%, in 1986. Since then, the economy has undergone a slow but steady recovery. Unemployment was at 3.4% in 1999. Gains in manufacturing made up for the losses in mining. Manufacturing output, however, peaked in 1999, and by 2001 had fallen 9.2%. The state's overall growth rate, which accelerated from 3.5% in 1998 to 3.9% in 1999 to 6.5% in 2000, fell back to 3.2% in the national recession and slowdown of 2001. The main growth sectors in terms of output coming into the 21st century (1997 to 2001) were general services (up 26.8%), government (up 24.2%), financial services (up 2.5%) and trade (up 21.3%). The impact of the national slowdown is expected to be mitigated by Oklahoma's military installations (Fort Sill and Tinder Air Force Base are two of the state's top five employers) in a time of rising defense spending, and by its oil and gas industry as prices reach new highs in 2003.
In 2001, Oklahoma's gross state product gross state product was $93.9 billion, the 29th largest among the states, to which general services contributed $17.6 billion; government, $15.8 billion; trade, $15.4 billion; manufacturing, $13 billion; financial services, $11.9 billion; transportation and public utilities, $8.8 billion; and construction, $3.9 billion. The public sector in 2001 constituted 16.8% of gross state product, well above the 12% average for the states.