Wealth concentration is at peak levels. That was the gist of a recent report published by the Institute for Policy Studies, a left-leaning think tank based in Washington, D.C.. Using data from Forbes' annual ranking of the 400 richest Americans, the institute reached a number of conclusions regarding wealth disparities in the United States. Most dramatically, it found that the country's three richest individuals - Bill Gates, Warren Buffett and Jeff Bezos - collectively hold more wealth than the bottom 50% of the domestic population, "a total of 160 million people or 63 million American households." Roughly a fifth of Americans "have zero or negative net worth," the authors wrote. Over the years, the cutoff for The Forbes 400 has risen dramatically. In 1982, the ranking's inaugural year, the minimum net worth was $100 million. This year the barrier to entry hit an all-time high of $2 billion. In its report, the think tank also found that, collectively, the individuals on The Forbes 400 hold more wealth than the bottom 64% of the country, "more people than the populations of Mexico and Canada combined." Altogether, the list members were worth $2.7 trillion this year, a 59% increase over the last five years alone. The net worth of the median American family, meanwhile, has declined by about 3% on an inflation-adjusted basis since Forbes began publishing the 400 in the early 1980s, the institute says. It reports that the typical U.S. family is presently worth some $80,000.