Problem: How much change has taken place through the years among the industries that have been the source of wealth for America's richest individuals?
What does this say about the changing nature of the economy?
See the following graph/chart.
FIGURE: The Form of Diversity of State Interest Communities, 1980, 1990, and 1997 Source: Virginia Gray and David Lowery, “The Institutionalization of State Communities of Organized Interests,” Political Research Quarterly 54: 271 (2001).