Nearly 7 percent of Sonoma County households earn more than $190,000 a year, placing them among the top 5 percent of income earners nationally.

While that's a lot more than many counties in Kentucky, Missouri, Montana and Idaho, it pales in comparison to the rest of the Bay Area.

Take Marin County, where nearly 19 percent of all households are in the national top 5 percent, or San Mateo and Santa Clara counties, where more than 16 percent of households are among the 5 percent.

Only Solano County, at 6.18 percent, has a lower share of its households meeting the threshold, according to a recent report by the U.S. Census Bureau.

The report, which is based on five years of surveys from the American community survey from 2007 to 2011, showed that most upper-income households lived in high population counties, particularly along the nation's coasts.

In California for example, counties with the highest concentration of upper-income households run contiguously from Sonoma County all the way down to San Diego County. North of Sonoma County, the statistics take a precipitous fall.

"In many ways we're more like the Greater Bay Area than we are like Del Norte or Humboldt," said Ben Stone, executive director of the Economic Development Board.

Of the nine counties in the Bay Area, Stone said Sonoma County shares more in common economically with Napa and Solano. In Napa County, just over 9 percent of households are considered upper-income by national standards.

In Lake and Mendocino counties, only 1.98 and 2.39 percent of households, respectively, are considered among the upper-income level.

Stone and Jonathan Coe, president and CEO of the Santa Rosa Chamber of Commerce, said the data are signs of opportunity for businesses and entrepreneurs considering locating in Sonoma County. Combined with high levels of educational attainment among the local population, Sonoma County is a far more affordable place to do business than elsewhere in the Bay Area, Coe said.

"It reflects a slightly lower wage scale," he said, adding that the county also has more affordable commercial space and an enviable quality of life.

"A lot of us would argue that Sonoma county is la cr?e de la cr?e," he said. "Put all that together and it becomes significant."

Recent census income data show dramatic differences in income levels for different geographic areas. For example, the lower limit of the top five percent of household incomes in Lake County is $140,786, compared to $141,204 in Mendocino County and $214,405 for Sonoma County.

In San Mateo County, the upper limit of income for the poorest 20 percent of households is $38,880. In Sonoma County, that figure is $27,559 and in Lake County it's 16,838, which is below the federal poverty threshold of $19,090 for a family of three.

(You can reach Staff Writer Martin Espinoza at 521-5213 or martin.espinoza@pressdemocrat.com.)