D.C., Maryland, and Virginia aren’t just growing in terms of sheer population. The city and its suburbs are also seeing increasing concentrations of wealth, as measured by households earning more than $200,000 a year at least.

The consulting firm Webster Pacific looked at Census data, highlighting areas that have seen the biggest increases in high earners over the past 17 years. Nearly one third of the top 100 are in the D.C. region, Bloomberg News reports.

Around the country, only 6.9 percent of American households take in $200,000 or more in a given year. In this region, though, there are some Census tracts where more than half the population earns that much.

Even with already significant concentrations of wealth at the turn of the 21st century, the D.C. area still has four out the top 10 areas with the fastest-growing population of high earners, according to Bloomberg. There are more than a dozen census tracts in D.C. proper where high-earning households have increased by 10 percentage points or more, in addition to pockets all around the region, per Bloomberg’s map. Certain parts of Loudoun County, Arlington, and Falls Church have seen growth of more than 20 percentage points.