OPEC oil production declined in August as Iranian output dropped to a 22-year low after new sanctions came into effect, a survey showed.

Production slipped 75,000 barrels, or 0.2 percent, to an average 31.988 million barrels a day this month from a revised 32.063 million in July, according to the survey of oil companies, producers and analysts.

Output in Iran, the Organization of Petroleum Exporting Countries’ third-largest producer, declined 350,000 barrels to 2.75 million barrels a day, the lowest level since February 1990.

Sanctions aimed at stopping Iran’s nuclear program have hindered its ability to export crude oil.

A European Union ban on the purchase, transport, financing and insurance of Iranian oil came into effect on July 1.

“We see the big fall from sanctions starting to stop now,” said Samuel Ciszuk, an analyst at KBC Energy Economics in Walton-on-Thames, England. “It may drop a bit more next month but then it will stabilize.”

Iraqi production increased 15,000 barrels to 2.98 million a day this month, matching April, which was the highest level since October 2000. The country’s production had been depressed since the U.S.-led invasion in March 2003.

Saudi Arabia pumped 9.9 million barrels a day this month, unchanged from July.

OPEC, provider of about 40 percent of the world’s oil, maintained its official production ceiling at 30 million barrels a day at a meeting in Vienna on June 14. Ministers from the group’s 12 members are next scheduled to gather on Dec. 12.