Question: Shares of Pitney Bowes dropped 10 percent after it announced earnings per share from continuing operations of $0.70 for its September quarter of 1999, up from $0.49 in the same quarter in the year before. Revenues also increased 8 percent. Analysts raised concerns about the quality of the earnings, citing a decrease in the firm's effective tax rate. Why might the effective tax rate be of concern to analysts?