U.S. manufacturing activity grew more slowly in February as U.S. factories received fewer new orders and paid higher prices for raw materials, a trade group reported Thursday. The Institute for Supply Management (ISM) said its manufacturing index fell last month to 52.4 from 54.1 in January. The reading was the lowest since November, but any reading above 50 indicates expansion in the sector. The U.S. manufacturing sector has expanded for 31 consecutive months, according to the index. New orders increased in January, but at a far slower pace than in the previous month. Production and employment also grew more slowly. Exports rose sharply, a sign that the European debt crisis has not yet limited overseas sales by U.S. factories. Manufacturing has grown partly because consumers are spending more on cars, appliances, and computers. Auto sales have rebounded strongly from spring 2011, when the earthquake and tsunami in Japan interrupted supply chains and fewer cars were available. The Federal Reserve (Fed) reported Wednesday that auto manufacturing, steel makers, and other metal producers reported solid growth in recent months.