ByJohn S. McClenahen Although the optimism index of National Federation of Independent Business (NFIB) has been at or above 100 for 14 months, it slipped just under a point between April and May to 104.5 (1986=100) as, among other factors, the net percentage of small business owners expecting the U.S. economy to improve fell five percentage points to 29%. Inflation fears seem to be the culprit. "This past September, virtually no firms were raising prices; now price hikes are pervasive in all industries," says the NFIB. The business group's researchers, however, are characterizing the slight April-to-May decline in optimism as a "breather" and reasserting that "2004 could be the best economy in two decades."