Something that caught my eye in a blog post by Paul Krugman:
This is not an unfamiliar graph, but it is always a bit startling to see it. Income inequality is soaring in the US. The Gini coefficient is the most popular measure of income inequality and ours is growing quite rapidly. What does this mean from a relative perspective? Here is a table I put together from data amassed in the CIA World Factbook:
Aside from any moral and ethical interpretations, what of the economic implications? What do we know about the relationship between inequality and growth in the data? Not much.
Here is a nice graphic from Wikipedia that shows how the Gini is calculated from a Lorenz Curve - the Gini is A/(A+B):