China's growth softened in 2013's fourth quarter as indicated by the purchasing managers' index both in manufacturing and non-manufacturing, UPI quoted economists as saying.The PMI for the manufacturing sector, which is a key measure of factory output, fell to 51 percent in December from November's 51.4 percent. The December data was the first such decline since June. Any number over 50 on the PMI index denotes expansion while any number below that denotes contraction. Similarly, the PMI for the non-manufacturing sector, which measures business activity in the services sector, fell to a four-month low at 54.6 in December as most industries sought to find new growth engines amid slowing exports.Xinhua News Agency said the final official data for the fourth quarter and for all of last year, including gross domestic product growth, industrial production, retail sales and fixed-asset investment, would be released later this month.