US ECONOMY SHRINKS - FIRST TIME IN NINE YEARS

The United States economy shrank for the first time in nine years during 1991, the Commerce Department said yesterday, and last year's closing quarter was even weaker than estimated a month ago.

In the final three months of 1991, national output expanded at only a 0.4 percent annual rate instead of 0.8 percent, the department said in a second and final revision of its growth estimates for the quarter. As a result, for all of 1991, total production of goods and services contracted by 0.7 percent - the first decrease in annual output in nine years since a 2.2 percent fall during the recession year 1982.

The department said the main factors in revising down its fourth-quarter estimate for gross domestic product were weaker exports than previously estimated as well as a smaller economic contribution from restocking of inventories.

The GDP is expected to grow at a more vigorous pace this year, with many economists forecasting annual rates of growth of 2 to 3 percent in the first half.