ByJohn S. McClenahen Although the U.S. Commerce Department is slated to revise the figure twice between now and the end of the year, its first estimate is that the U.S. economy grew at a torrid inflation-adjusted 7.2% annual rate from July through September. That was more than twice the second-quarter's 3.3% rate and the fastest growth rate for GDP since the first quarter of 1984. Consumer spending, which accounts for about two-thirds of U.S. economic activity, was a major factor in the economy's strong showing, rising 6.6% in the third quarter of this year, compared with 3.8% during the second quarter. "This is very good news for America's manufacturing base, because it signals that a broad-based strong cyclical recovery -- essential for a meaningful rebound in manufacturing output and employment -- has finally arrived," says David Huether, chief economist at the National Association of Manufacturers, Washington, D.C. Among the more notable GDP data released on Oct. 30: Spending on equipment and software increased 15.4% during the third quarter, nearly twice the 8.3% increase during the second quarter of this year. "The best news . . . is that business investment is finally coming back strongly," says Thomas J. Duesterberg, president and CEO of Manufacturers Alliance/MAPI, an Arlington, Va.-based business and public policy research group. "Combined with low inventories that need to be rebuilt, better export performance and a stronger labor market, this bodes well for continued robust growth into 2004."