New York, May 1 (BridgeNews) - The manufacturing sector contracted for the ninth straight month in April, but prices are falling and businesses are working through their backlog of inventory, the National Association of Purchasing Management reported. The group said its index of economic activity in manufacturing rose to 43.2 in April from 43.1 in March, but remained below 50.0, the dividing line between economic growth and contraction. Economists had expected a reading of 43.5.