What are the causes?

A prime example is the United States for instance. The income share of just the top one half of the top one percent grew from 5.39 percent of the nations income in 1979 to 13.37 percent in 2010. By contrast, over the same time period the share of the bottom 90 percent fell from 67.65 percent to 53.74 percent of the nations wealth. Yet again, keeping the rich more richer while the poor just keep getting more and more poor.

A grotesque depiction of the rapid inequality. 

First, they focus largely on the relatively high wages of the 90th percentile of earners to that of the 10th percentile, which misses the fact that much of the increase in inequality was well above the 90th percentile. Again, with the United States as an example, growth in wages at the 90th percentile of wages only just kept pace with the overall average. Ninety percent of the distribution failed to keep up.