The purchasing managers' index (PMI) for China's manufacturing sector came in at 51.9 in March, down from 52.6 in February, data from the National Bureau of Statistics showed Friday.A reading above 50 indicates expansion, while a reading below reflects contraction.The purchasing managers' index (PMI) for China's manufacturing sector came in at 51.9 in March, down from 52.6 in February, data from the National Bureau of Statistics showed Friday.A reading above 50 indicates expansion, while a reading below reflects contraction.