Source: Energy Information Administration, Interagency Database and Projections Working Group and Worldwatch Institute.

Real Price of Oil and Major Disruptions in World Oil Supply, 1950-2008

Prior to the 1973 OPEC Embargo, disruptions in oil supply had no impacts on oil prices. During that period, oil production was dominated by the United States, which provided 52% of the world's oil in 1950. By 1997, this share dropped to 10%. The early 1970s were pivotal as the balance of power shifted to OPEC, since they accommodated most of the supplementary oil production derived from rising demands in developed countries. The Iranian Revolution of 1979 and the Iran / Iraq War a year after caused major disruptions and raised oil prices significantly.