Growth picked up last month for the U.S. service sector and other non-manufacturing companies, according to data released Monday. The Institute for Supply Management said its non-manufacturing index rose to 55.2% in April -- the highest reading in six months -- from 53.1% in March. Economists had expected an April reading of 54.2%. Readings over 50% signal expansion -- the higher the reading, the faster the expansion. ISM said the new-orders barometer rose 4.8 points to 58.2%, and the business activity/production barometer increasd 7.5 points to 60.9%. Meanwhile, the non-manufacturing employment gauge fell 2.3 points to 51.3%. Among 18 industries tracked by ISM, 14 reported growth last month, while four contracted.