The nation's purchasing managers said the U.S. economy grew strongly during October despite the stock market turmoil. The National Assn. of Purchasing Management said its monthly indicator rose to 61.8% last month, the highest level since December, 1983, and 1.1% above September. An index reading above 50 indicates the economy is expanding and below 50 indicates a decline. The index consists of business indicators gathered from a monthly survey of purchasing executives at 250 industrial companies.