According to the Census Bureau there has been a growing income disparity in the United States over the past two decades. The wealthiest 20 percent of households accounted for 50 percent of total U.S. income in 2002, while the share for the bottom fifth dropped from 4.2 percent to 3.5 percent. Economists attribute this widening gap to a shift in the structure of the economy. Increased globalization and technology have put highly skilled and educated workers in demand, while making the jobs of lower skilled workers vulnerable to outsourcing.
See "Income Gap Up Over Two Decades, Data Show", The New York Times, August 16, 2004