The U.S. manufacturing sector continued to expand in April, but the rate of growth slowed, a leading industry survey showed on Wednesday. The U.S. Institute of Supply Management (ISM) said the manufacturing index, also known as the purchasing managers index (PMI), edged down from the reading of 51.3 percent in March to 50.7 in April. A reading above 50 percent indicates that the manufacturing sector is generally expanding, while a reading below 50 percent indicates contraction. The new orders index rose to 52.3 percent last month from 51.4 in March. The production index stood at 53.5 percent in April, an increase from 52.2 percent in March. However, the employment index registered 50.2 percent, a decrease of 4 percentage points compared to March\'s reading of 54.2 percent. Of the 18 manufacturing industries, 14 reported growth last month including electrical equipment and transportation equipment. Three industries including chemical products reported contraction, said the ISM. Manufacturing has been a bright spot in output and employment since the recession ended in June 2009. But the sector has shown signs of fluctuation in recent months.