By John S. McClenahen Don't be overly concerned by Dec. 11's report from the U.S. Labor Department showing that import prices in November had picked up at twice the rate economists had anticipated. The department's Producer Price Index (PPI) for November, released Dec. 12, showed that prices for finished goods decreased 0.3%. That's dramatically lower than the 0.1% increase economists generally expected, and the decline comes after five consecutive monthly increases in the PPI, including a remarkable 0.8% advance in October. "The PPI data . . . are in keeping with the Fed's goal of achieving price stability," says David A. Rosenberg, chief North American economist at Merrill Lynch & Co., New York.