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Capital Bikeshare is growing. Its members are saving money: on average, $13.65 per week, or $710 a year; in aggregate, nearly $20 million a year. They’re reducing crowding on city streets and public transit: 55 percent drive less now that they use Bikeshare, 59 percent takes fewer cabs, 58 percent reduced Metro usage, and 52 percent cut their bus trips.

That’s the good news out of Bikeshare’s latest annual member survey, first reported in the Washington Post. The bad news is that the Bikeshare system is becoming less diverse.

In Bikeshare’s 2012 survey, 80 percent of members were white. Last year, that number rose to 84 percent. (Compare that to the overall workforce in the region, which is just 50 percent white.) Members’ household incomes have climbed sharply, with the percentage making more than $100,000 a year rising from 39 percent in 2011 to 45 percent in 2012 to 50 percent last year. Men’s share of Bikeshare members has also steadily increased, from 55 percent in 2011 to 57 percent in 2012 to 59 percent in 2014.

Here’s how Bikeshare members compare to regional workers in a few demographic categories.

They’re much more male than the average:

They’re much whiter than the average:

And they’re much younger than the average, even if the median age of Bikeshare member has climbed slightly over the past three years:

But here’s the chart that goes a long way toward explaining all the trends laid out above. With Bikeshare expanding in suburban jurisdictions, members increasingly live and work outside of the District, in the inner suburbs that tend to be a lot wealthier and whiter than D.C.:

Photo by Darrow Montgomery; charts via Capital Bikeshare