By many measures, the U.S. economy is doing well: the labor market is strong, monetary policy remains largely accommodative for the moment, and corporate America is expected to post its best quarter of profit growth in seven years. Despite that, economic growth has been fairly tepid, and it could be because any improvements in the economy are being unequally distributed.

According to Torsten Sløk, the chief international economist at Deutsche Bank Securities, income inequality is a major factor that has been holding back the U.S. economy for nearly a decade.

“One important reason why the expansion since 2009 has been so weak is that wealth gains have been unevenly distributed,” he wrote. “A decline in the homeownership rate and the number of households holding stocks has dampened consumer spending growth for the bottom 90% of households.”

Per his data, the median net worth for all income percentiles except the wealthiest one dropped between 2007 and 2016, usually by double-digit amounts.

For the poorest American families, in the lowest fifth of wealth, their net worth shed 29% over that period. Drops of at least 20% were also seen in every income percentile except for those in the 80-89.9 percentile, where the decline was a more modest 5%. The wealthiest decile, however, saw a jump of 27%, as seen in the following chart.

Courtesy Deutsche Bank Securities

America actually ranks among the worst countries when it comes to income inequality, based on its Gini coefficient, a measure of the wealth distribution of a country’s residents. The coefficient for the U.S. is nearly 0.40, which puts it roughly even with Turkey, and above such nations as Israel, Greece, Spain, and Germany. Iceland, the most equal society measured by Deutsche Bank, has a coefficient below 0.25.

The lower the Gini coefficient, the more equal the income distribution.

Read: One theory why income inequality has grown in America

Also:The harsh truth about economic inequality, based on thousands of years of evidence

According to Sløk’s data, which is derived from DB Global Markets Research and the World Wealth and Income Database, the richest 0.1% of Americans owns as much as the entire bottom 90%, a trend that has been accelerating since the mid-1980s, while the richest 1% earn more than a fifth of total income in the U.S.

The wealthiest 10% own nearly 90% of stocks, the highest such ratio since 1983, meaning that the sharp gains seen in the Dow Jones Industrial Average DJIA, +0.51% and the S&P 500 SPX, +1.05% since the financial crisis bottom in 2009 have had little broad impact for most Americans.

Read more:Why only a tiny percentage of Americans benefit from Dow 25,000

Learn more:This is what income inequality means for your 401(k)

Last year, billionaire hedge-fund titan Ray Dalio said that “the greatest issue of our time is the disparity of wealth and the problems that exist for the lower 40% of the population.”

He added, “If you carve out that lower 40%, not only has there been no income growth, but death rates are rising because of opiate use, suicide, and because they’re losing jobs. This is the biggest issue of our time—the biggest economic issue, the biggest political issue, and the biggest social issue.”