How skewed is America's income inequality? Take our quiz.

Income inequality has become a central issue in the presidential election, with President Obama declaring it “the defining issue of our time,” Mitt Romney decrying “the bitter politics of envy,” and Romney’s former Bain partner (and current campaign contributor) Edward Conard arguing, in a new book, that income inequality is something America needs more of. To evaluate what the candidates say in the coming months, you’ll need a working knowledge of the topic. How well do you know American inequality? Take this quiz based on my new book, "The Great Divergence":

- Timothy Noah, Contributor

Question 1 of 20

1. Income inequality has been growing in the US since:

Avi Mirman, right, who works on Wall Street, stops to talk with Occupy Wall Street protesters Jo Robin, second from right, and Evan Wagner, third from right, in front of the New York Stock Exchange in New York, in April. (Seth Wenig/AP/File)