Iran is the fourth oil-rich country (157 billion barrels of proven oil reserves) and the first natural gas-rich country (33.8 trillion cubic meters of proven natural gas reserves) in the world. Before the implementation of sanctions, Iran was the second largest crude oil exporter among the Petroleum Exporting Countries (OPEC) after Saudi Arabia (the fifth largest after the sanctions) and was the fourth largest crude oil exporter country in the world. Oil and gas products account for about 80-90% of total exports of the country, which is 40-50% of the state budget income.