ByJohn S. McClenahen A group of leading American CEOs expects the U.S. economy to grow 3.5% next year, right in line with its long-term growth potential, although less than the 4%-plus rate widely anticipated for this year. "CEOs are forecasting continuing solid growth with a slight easing from the robust growth of 2004," says Henry McKinnell, chairman and CEO of Pfizer Inc. and current chairman of the Washington, D.C.-based Business Roundtable, which released its latest economic forecast earlier this month. According to its latest survey, which included 131 CEOs of the Roundtable's 160 member companies, 85% expect their companies' sales to increase during the first six months of 2005, 50% expect to increase capital spending, and 40% expect to add jobs.The CEOs cite health care costs, litigation costs, and energy prices as the greatest challenges to their companies' growth.