U.S. airstrikes lower oil production to 21,000 barrels a day U.S.-led air strikes and territorial gains by forces allied with Russia and Iran have cut Islamic State’s monthly revenue by almost 30 percent over the past year, according to a report by IHS Inc. The terrorist group, which earns about half its revenue from taxation and confiscation, has lost about 22 percent of its territory in Iraq and Syria over the past 15 months, according to Englewood, Colorado-based IHS, which provides advice to businesses and governments. That will hamper the group’s ability to recruit new soldiers, pay existing supporters and sustain basic services in areas it controls. “The Islamic State […]