The terms oil production and gas production refer to rates of extraction of liquid and gaseous hydrocarbon materials from natural underground deposits. Reserves and resources, on the other hand, refer to amounts of oil and gas that are present in the deposits, the difference between reserves and resources being whether or not the amounts can be economically recovered under current conditions. Supply refers to the amount of a product that becomes available for use in a given time, such as a year.

Worldwide production of crude oil increased through 1998 in response to increasing demand, although U.S. production was declining. The annual world supply of oil, which includes the annual production of crude oil and natural gas liquids grew from eighteen billion barrels in 1970 to twenty-seven billion barrels in 1998. A barrel is forty-two U.S. gallons. At the same time...