The chart is taken from an article in the New York times.

Incidentally it illustrates the 'Pareto Principle'. Vilfredo Pareto (1848-1923) was an Italian economist. He noticed that 20% of the people of Italy owned 80% of the wealth. It has been found that this principle applies to economies generally, and also to other areas of life.

The Pareto Principle is important in quality and process improvement ('Six Sigma') because 80% of quality problems arise from 20% of the possible causes. An important first step is to identify the 'important few' among the 'trivial many', and give those most attention.

Why do I claim that the figure shows that the distribution of net worth obeys the Pareto principle?