"The productivity of U.S. workers dropped for the first time in two years during the first three months of the year, the Labor Department reported yesterday.</br></br>The decline burst a bubble of increasing productivity that had many economists wondering whether U.S. gains in economic efficiency were moving to a higher track.</br></br>""It's disappointing, but we had such a phenomenal string of gains that some setback was expected,"" said economist Stephen S. Roach of Morgan Stanley & Co. in New York, according to the Associated Press. ""I'm convinced we're on a path of higher productivity growth in the 1990s.""</br></br>Productivity at American businesses - the amount of goods and services produced for each hour worked - fell at an annual rate of 1.5 percent in the first three months of the year, the department said in revising an earlier report.</br></br>The department had earlier estimated that overall business productivity grew at a 0.1 percent rate in the first quarter."