The U.S. lost about 1 percent of the oil production flowing from its shale formations this month, and the decline is just starting. Output from the prolific tight-rock formations such as North Dakota’s Bakken and Texas’s Eagle Ford shale will slide 54,227 barrels a day this month, based on Energy Information Administration estimates. It’ll fall another 86,000 barrels in June to a five-month low of 5.56 million, the agency said Monday. Last year’s plunge in crude prices led to the steepest and most prolonged retreat from U.S. oil fields on record. Drillers have idled more than half the country’s rigs and eliminated tens of thousands of jobs. Some of the country’s largest shale producers including ConocoPhillips and EOG Resources Inc. have said spending cuts […]