| Historically, crude oil or petroleum prices | | | | importing increasing quantities of crude |
| in the United States have been affected by a | | | | oil.Up until the 1972 war between Israel and |
| variety of global factors. In the beginning | | | | Syria and Egypt, global crude oil prices were |
| of the 20th century, crude oil production | | | | fairly stable at about $3 a barrel. An oil |
| began to be controlled by the US government, | | | | embargo by major oil-producing countries in |
| with restrictions on the amount of production | | | | 1973 led to the first steep increase in crude |
| and price to conserve this valuable energy | | | | oil prices, to $12 a barrel. Following the |
| source. Following the Second World War, | | | | Iran revolution of 1979 and the Iran-Iraq |
| demand for petroleum could not be met through | | | | war, crude oil prices rose to $35 a barrel by |
| local production alone, and the US started | | | | 1981. |