As of 2018, the 15 countries accounted for an estimated 44 percent of global oil production and 81.5 percent of the world’s “proven” oil reserves, giving OPEC a major influence on global oil prices that were previously determined by the American-dominated so called as “Seven Sisters” grouping of multinational oil companies.
In its early years, OPEC faced significant challenges, including skepticism from both oil-consuming countries and multinational corporations. Despite these obstacles, OPEC gradually gained influence, particularly during the 1970s oil crises, when the organization demonstrated its ability to influence global oil prices through production quotas and supply control.
