Stop me if you've heard this one: The top 1% of Americans controls 40% of the wealth.

It's true. But that might not be the most shocking number about wealth inequality in the United States.

I recently sat down with Chrystia Freeland, editor of Thomson Reuters, for a wide-ranging interview on the state of the economy. We got to talking about the growing level of wealth inequality and, importantly, why it seems to be gaining steam and how it affects the economy.

She had some fascinating perspectives. Not only has technology flattened the world and brought billions of new workers into the competitive labor market -- think about how Google and Facebook have connected everyone -- but a decline in taxes among high-income workers, a decline in labor unions, and a cultural shift that promotes CEOs making enormous pay packages have all played a role in the growing disparity between the middle class and the top of the pyramid. Have a look: