Iran and these four other countries are the world’s biggest oil producers, according to 2010 data from the U.S. Energy Information Administration.
No. 5: Iran Bahman Famil Khalili works at Tehran's oil refinery. Iran produces 4.3 million barrels of oil a day. Iran is one of the Organization of the Petroleum Exporting Countries (OPEC) founding members. Vahid Salemi/AP