August 3, 2012. U.S.-led sanctions against Iran are costing OPEC's third-largest producer $133 million a day in lost sales without raising global crude prices, handing President Barack Obama an election-year foreign-policy victory. Shipments from Iran have plunged by 1.2 million barrels a day, or 52 percent, since the sanctions banning the purchase, transport, financing and insuring of Iranian crude began July 1. Annualized, that would cost President Mahmoud Ahmadinejad's country about $48 billion in revenue, equivalent to 10 percent of its economy. While Iran's threats to disrupt the flow of oil through the Persian Gulf sent crude to a three-year high in March, increased production from Saudi Arabia, a U.S. output boom and the slowing global economy have left prices 1 percent lower in 2012. That's helping Obama avoid steeper domestic fuel costs before the November presidential election. Iran has to contend with a weakening currency and rising unemployment. Crude futures in London rose as high as $128.40 on March 1, an advance of 20 percent for the year, after Iranian officials threatened to order the closing of the Strait of Hormuz. The Gulf waterway, 21 miles wide at its narrowest, is a conduit for 20 percent of the world's traded oil. Prices retreated as Saudi Arabia boosted output. The Organization of Petroleum Exporting Countries' biggest producer is pumping more than 10 million barrels a day, the most in three decades and 22 percent more than at the end of 2010. The Paris-based adviser to the world's biggest industrialized economies cut its forecast for global oil use four times this year, to 89.9 million barrels a day. Iran is exporting 1.1 million barrels a day of oil. The lost sales are valued at $133 million a day, based on the 2012 average price of $110.60 a barrel for Iran Heavy crude in Asia.