The US has the largest and most technologically powerful economy in the world, with a per capita GDP of $36,300. In this market-oriented economy, private individuals and business firms make most of the decisions, and the federal and state governments buy needed goods and services predominantly in the private marketplace. US business firms enjoy considerably greater flexibility than their counterparts in Western Europe and Japan in decisions to expand capital plant, lay off surplus workers, and develop new products. At the same time, they face higher barriers to entry in their rivals' home markets than the barriers to entry of foreign firms in US markets. US firms are at or near the forefront in technological advances, especially in computers and in medical, aerospace, and military equipment, although their advantage has narrowed since the end of World War II. The onrush of technology largely explains the gradual development of a "two-tier labor market" in which those at the bottom lack the education and the professional/technical skills of those at the top and, more and more, fail to get comparable pay raises, health insurance coverage, and other benefits. Since 1975, practically all the gains in household income have gone to the top 20% of households. The years 1994-2000 witnessed solid increases in real output, low inflation rates, and a drop in unemployment to below 5%. The year 2001 witnessed the end of the boom psychology and performance, with output increasing only 0.3% and unemployment and business failures rising substantially. The response to the terrorist attacks of September 11 showed the remarkable resilience of the economy. Moderate recovery is expected in 2002, with the GDP growth rate rising to 2.5% or more. A major short-term problem in first half 2002 was a sharp decline in the stock market, fueled in part by the exposure of dubious accounting practices in some major corporations. Long-term problems include inadequate investment in economic infrastructure, rapidly rising medical and pension costs of an aging population, sizable trade deficits, and stagnation of family income in the lower economic groups.