The Richmond Manufacturing Index measures the conditions of the manufacturing sector for the District of Columbia, Maryland, North Carolina, South Carolina, Virginia, and most of West Virginia. The index is derived from a survey of 190 manufacturing plants and based on three individual index with the following weights: Shipments (33 percent), New Orders (40 percent) and Employment (27 percent). The index can range between +100 and -100; a reading above zero indicates expansion, while below zero suggests a contraction.