Majority of oil produced by non-OPEC countries

While tensions mount in the Middle East, most oil production comes from outside OPEC. In August, non-OPEC producing countries produced 73.3 million barrels of oil a day, or about 73% of the global production. OPEC countries' oil production was 27.4 million barrels a day.

Last year, the U.S. was the world's largest oil producer with 20.3 million barrels per day, or 21% of the worldwide total, according to the U.S. Energy Information Administration. Saudi Arabia followed at 12.4 million barrels a day, and Russia remains a major producer with 10.1 million barrels a day.

The West Texas Intermediate crude oil price closed at $85.97 per barrel on Oct. 10, down from $86.38 the previous day. Before the Middle East hostilities escalated, WTI was $82.79 on Oct. 6. At the end of September, WTI crude oil closed near $94 a barrel.