Wealth, like income and taxes, is highly concentrated; the richest 10% of the adult population possess 72% of the country's household wealth, while the bottom half possess only 2%. According to the Federal Reserve, the top 1% controlled 38.6% of the country's wealth in 2016. In 2017, Forbes found that just three individuals (Jeff Bezos, Warren Buffett and Bill Gates) held more money than the bottom half of the population. According to a 2018 study by the OECD, the United States has a larger percentage of low-income workers than almost any other developed nation, largely because of a weak collective bargaining system and lack of government support for at-risk workers. The top one percent of income-earners accounted for 52 percent of the income gains from 2009 to 2015, where income is defined as market income excluding government transfers.