The U.S. economy weakened sharply in July.

According to figures released by the National Assn. of Purchasing Managers, the organization’s composite index fell to 46.7% from 49.6% last month. The survey is one of the quickest indicators of the nation’s economy. The index measures new orders, production, deliveries, inventories and employment. “Fueled by seasonal plant shutdowns, the economy continued to weaken in July,” Chairman Robert Bretz said. “For the second consecutive month, virtually all indicators were off, a disturbing trend if it doesn’t end soon.” The association said much of the July production drop could be linked to planned plant shutdowns.