FACTBOX: OPEC quotes on the tumbling dollar

(Reuters) - The Organization of the Petroleum Exporting Countries (OPEC) agreed its finance ministers would meet to discuss the sliding dollar after Iran and Venezuela recommended pricing oil against a currency basket.

-The world's top oil exporter Saudi Arabia blocked a proposal by Iran and Venezuela to include mention of the weak dollar in the final declaration at an OPEC heads of state summit on November 17-18.

-Saudi Arabia and key Gulf producers the UAE and Kuwait price all of their oil in dollars. They supply around 16 percent of the world's oil. Anything that weakens the dollar will also hurt the region's massive dollar-weighted investments.

-Most of the world's oil is priced in dollars. The world's largest oil futures exchanges the New York Mercantile Exchange (NYMEX) and the InterContinental Exchange (ICE) both price oil in dollars. Most international oil contracts use dollar benchmarks for pricing.

-Iran is the only OPEC member that has asked buyers of its oil for payment in non-dollar currencies. It gets about 70 percent of its oil revenues in other currencies, but the percentage varies monthly. The move by Iran was in part politically motivated as the row drags on with the United States over Tehran's nuclear ambitions.

Following are key quotes on the dollar and its impact on oil producers' economies from a meeting of OPEC heads of state, energy and finance ministers in Riyadh. Click on the codes within square brackets for details.

IRAQ'S FINANCE MINISTER

"There was a proposal from Iran and Venezuela to have a basket of currencies for the pricing of OPEC oil. But a consensus could not be reached," Bayan Jabor said.

"Because the final communique was already drafted there was an agreement that OPEC finance ministers hold a meeting before the oil meeting in the UAE in December to discuss economic issues including the dollar's exchange rate."

SAUDI FOREIGN MINISTER

"I think we should leave this matter to the competent parties... and not include it in the communique's draft," said Saud al-Faisal. "My fear is that any mention that OPEC makes of studying the issue of the dollar, will in itself have an impact."

OPEC'S SECRETARY-GENERAL

"Yes, we are concerned. But this is a discussion among ourselves and this is not the first time we have discussed it," Abdullah al-Badri said.

QATAR'S ENERGY MINISTER

"Today we feel concerned because of the very large decline in the value of the dollar. This has a very big impact on oil-exporting countries," Abdullah bin Hamad al-Attiyah said. Qatar's "purchasing power has fallen considerably," he said.

IRAN'S PRESIDENT