There\'s very slow recovery under way in the U.S. economy as measured by petroleum deliveries for March, API Chief Economist John Felmy said. The American Petroleum Institute reported that U.S. petroleum deliveries, a measure of demand, were around 18.3 million barrels per day. That\'s a slight increase year-on-year, though U.S. petroleum deliveries for the first quarter of the year were down 0.4 percent compared to 2012. \"Tepid growth and high unemployment are still burdening the economy and holding demand down,\" Felmy said in a statement. \"The recovery is a sputtering engine with a cylinder or two still not firing.\" The U.S. Labor Department reported Thursday that first-time unemployment benefit claims rose 4,000 to 352,000 in the week. API said the United States produced 7.1 million bpd in March, contributing to a 14.1 percent gain from the first quarter of last year. The oil trade group said monthly output was the highest for March in 21 years. Imports were at their lowest level since 1998 at 10.0 million bpd, down 5.3 percent compared to last March. First quarter 2013 imports were down 6.5 percent compared to last year. The U.S. Energy Department, in its short-term energy outlook, expects U.S. crude oil production to go from an average of 6.5 million barrels per day recorded last year to 7.9 million bpd next year.