US manufacturing activity rises at fastest pace in 6 months and hiring at factories increases

``Manufacturing grew in December at the fastest pace in six months and hiring at U.S. factories picked up. The data helped bolster the view that the economy gained momentum at the end of last year. The Institute for Supply Management, a trade group of purchasing managers, said Tuesday that its manufacturing index rose to 53.9 from 52.7 in November. Readings above 50 indicate expansion.''