WASHINGTON — YES, we know the economic fortunes of the 99 percent and 1 percent have diverged over the last three or four decades. But the fortunes of the 1 percent and the 0.1 percent, or the 0.01 percent, or the 0.001 percent, have diverged even more. Economists have taken to calling it “fractal inequality.” It is not just that the rich have pulled away from the average American. It is that the richer you are, the more you have pulled away.

Consider some data from the World Top Incomes Database, put together by researchers at institutions including the Paris School of Economics and the University of California, Berkeley. It found that in 2012, the average household in the bottom 90 percent of the income distribution earned about $30,997. For the average household in the top 1 percent, the figure is $1,264,065, and for the top 0.1 percent, about $6,373,782.

Put another way, our 0.1 percent household made about 206 times, and our 1 percent household about 41 times, what our average household did. That gap has yawned over time. In 1990, for instance, the same multiples were 87 and 21. In 1980, they were 47 and 14.

To understand how that has happened, it helps to understand who the 1 percent and the 0.1 percent are. A broad range of professions are represented — artists and doctors and inheritors, lawyers and miners and university professors. But about two in five income earners who make it into the top 0.1 percent in a given year are executives, managers or supervisors. And one in five comes from the world of finance.