The longest economic expansion in U.S. history continued in 2000 and provided a stimulus for mineral materials demand. Economic growth, however, began to slow in the latter half of the year and was further dampened by higher energy costs and rising interest rates (U.S. Geological Survey, 2000, 2001). The slower economic growth, combined with declining growth rates in other industrialized economies, reduced production and shipment rates for U.S. primary metal products, particularly steel, late in the year. Moreover, low prices in the copper industry and high energy costs in the aluminum industry precipitated real declines in the output of both metals during 2000. Growth in the domestic production and shipments of nonmetallic mineral products also began to wane, particularly in the second half of the year (see page 3). Owing in part to a strong U.S. dollar relative to other currencies, lower prices and rising imports tended to restrain growth in the domestic output of processed metal and nonmetal mineral materials alike by year end.