ByJohn S. McClenahen The Conference Board's index of leading U.S. economic indicators fell 0.3% in August, the measure's third consecutive monthly decline. The New York-based business research group's leading index, which previews the U.S. economy by three to six months, now stands at 115.7 (1996=100). History suggests the index is signaling a recession. However, the declines "have not been long enough or deep enough to signal an end to the upward trend in the leading index underway since March 2003," the Conference Board insisted in a statement released on Sept. 23. The rate of growth for the leading index has slowed to an annual rate of 1% to 2%, figures the Conference Board, adding that the index's recent slower growth rate "is consistent with real GDP continuing to increase, but at or slightly below its long-term trend." Economists generally put the annual long-term growth rate of the U.S. economy at about 3.5%.