It may not have its own university, but it's easier to find a college graduate in the town of Sonoma than anywhere else in the county.

Nearly two in five adults in Sonoma have earned a bachelor's degree or better, making it home to the highest concentration of college grads in Sonoma County, according to new U.S. Census estimates released this month.

The figures paint a vivid statistical picture of life in Sonoma County, revealing not just the demographic makeup of its nine cities, but also their economic composition.

Not surprisingly, all those college degrees result in higher incomes. Residents in Sonoma make more money per capita than their neighbors in the county's other cities, according to the new census figures.

And they're grayer, too. A quarter of Sonoma residents are 65 or older, the largest share in the county.

The numbers don't surprise Sonoma Mayor Ken Brown.

"In 21st century America, there's no better place to live in than Sonoma," he said.

He said high education levels likely translate into greater civic involvement and voter participation. In the recent election, 87.1 percent of Sonoma's registered voters cast ballots. That's only slightly less than the 87.3 percent of Sebastopol's registered voters who participated in the recent election.

"We have a very informed participatory electorate that makes the city run and citizens have high expectations," said Brown.

For example, the county's fourth-smallest city boasts a world-class art museum that can exhibit the likes of Goya, Rembrandt and Picasso, as well as offer youth programs to fill the educational gap left by dwindling arts curriculum in local schools.

The income and education figures make sense, said Kate Eilersten, executive director of Sonoma Valley Museum of Art. Despite the city's small size, with 10,741 residents, the museum has a strong support base, with 1,000 members, and a group of donors who are committed to fostering a home-grown artistic and cultural resource.

"I've often said that a museum of this scale would never survive a town of this size," said Eilersten, who previously worked for the New York Metropolitan Museum of Art and Harvard University art museums in Cambridge, Mass.

Annual income, per resident, was $42,261 in Sonoma (in 2011 dollars), the highest of any city in the county. By comparison, the state's per capita income was $29,634 and the county's overall per capita income was $33,119.

The figures are based on an analysis of five years of results, from 2007 to 2011, from the Census Bureau's American Community Survey, the most precise census survey data available.

Cloverdale was the poorest of the county's nine cities, with a per capita income of $25,745. Given the long documented link between incomes and educational attainment, it may not be surprising that Cloverdale also had the lowest concentration of college grads, who make up just 21.5 percent of the city's residents.

By comparison, 39.2 percent of Sonoma residents hold a bachelor's degree or higher, according to Census Bureau estimates. That's higher than the county-wide figure, at 31.8 percent, or the state, at 30.2 percent.

Sebastopol and Petaluma came in a close second and third, with 38.9 and 35.4 percent of residents, respectively, who hold a bachelor's degree or higher.

To be fair, the census estimates of college-educated residents in the city of Sonoma has a 4.6 percent margin of error. For Sebastopol, it's 4.8 percent. That means that Sonoma's statistic could be as low as 34.6 percent and Sebastopol's could be as high as 43.7.