Growth picked up last month for the U.S. service sector and other non-manufacturing companies, according to data released Thursday. The Institute for Supply Management said its non-manufacturing index rose to 53.1% last month from 51.6% in February. Economists polled by MarketWatch had expected a March reading of 53.3%. Readings over 50% signal expansion -- the higher the reading, the faster the expansion. ISM said the non-manufacturing employment gauge shot higher, rising 6.1 points to 53.6% in March. Meanwhile, the new-orders barometer rose 2.1 points to 53.4%. Among 18 industries tracked by ISM, 13 reported growth last month, while five contracted