Manufacturing output grew at a rate of 3.8% per year from 1990 through 1998, and manufacturing's percentage of gross domestic product at a rate of 3.4%, reports the National Assn. of Manufacturers (NAM), in its latest economic study, American Manufacturing in the 1990s. Both numbers, says NAM, outpace the 3% growth of other nonfarm business sectors during the same period. "Manufacturing is strong, and the outlook for industrial growth is healthy," declared NAM President Jerry Jasinowski in releasing the report Mar. 26. "Reports of the manufacturing sector's decline are not just exaggerated, they are plain wrong." The key to manufacturing high growth, said Jasinowski, is productivity. The report indicates that manufacturing productivity has grown by 3.7% a year since 1990 -- double the rest of the economy -- and soared to 4.8% during the last three years. To keep manufacturing healthy, however, Jasinowski called for an across-the-board tax rate reduction of 10%, a permanent extension of the R&D tax credit, reform of the Alternative Minimum Tax rate structure, and expansion of the tax deduction allowed companies for reimbursing employees' tuition costs. Companies, he said, need to invest more in employee training.