Oil prices plunged more than 6 percent to the lowest in more than a year on Monday, pulling back sharply late in the session as fears of an economic slowdown rattled the market. U.S. crude futures and global benchmark Brent fell to the lowest since 2017 during the session, putting both benchmarks on track to lose about 40 percent in the quarter. “What’s happening in the stockmarket is raising fears that the economy is grinding to a halt and thereby will basically kill any future oil demand,” said Phil Flynn, an analyst at Price Futures Group in Chicago.