The United States' yawning income gap between the middle class and the top percentile isn't unique. It's part of a global phenomenon.
A new OECD report concludes that income inequality is rising in most developed countries. Here's the OECD's graph of Gini coefficients by country. Gini coefficients can theoretically range from 0.0 to 1.0, with higher values indicating greater inequality.
The relative rankings of inequality haven't changed much over two decades, with the United States leading the trend. But inequality is rising in most developed countries, literally upending the Kuznets curve - one of market fundamentalists' most cherished ideas.
The Kuznets Curve, named after Nobel Laureate Simon Kuznets, predicts that as nations become wealthier, inequality initially rises and then declines, like a single squeeze of an accordion. Economists hypothesized inequality would rise as workers transitioned from low-paying agricultural work to higher-pay industrial work, but that the lower classes would catch up once the industrial revolution completed. Kuznets himself thought that as a country grew wealthier, it would also implement more redistributive policy. Kuznets, who died in 1985, was more or less right, but only for his lifetime.