NORTH BAY -- The August unemployment rate dropped slightly in all but one North Bay county, according to data released by the Employment Development Department today, while the state and national rates edged slightly downward as well.

Marin, Sonoma, Mendocino, Lake and Solano counties all saw slight decreases in unemployment while Napa remained flat.

In Marin, part of the three-county West Bay Region that includes San Mateo and San Francisco counties, the unemployment rate was 8.4 percent in August, down from 8.6 percent in July. Marin has the lowest unemployment rate in California.

In Sonoma County, the rate dropped to 10.5 percent from July’s 10.9 percent, but still above the year-ago rate of 10.1 percent

Napa’s rate was unchanged at 9.4 percent over the month and above the year-ago rate of 8.8 percent.

Mendocino County saw a half point drop, from a revised 11.3 percent in July to 10.8 percent in August, but still up from last year’s rate of 10.3 percent.

Lake County also dropped half a point, from 17.3 percent in July to 16.8 percent in August, but two full percentage points up from this time last year.

California’s rate edged down to 12.4 percent from July’s 12.8 percent, while the national average went from 9.7 percent in July to 9.5 percent in August.

Unemployment rates for North Bay countiesCountyAugust 2009July 2010August 2010State rank

(out of 58)Lake14.8%17.3%16.8%53Marin7.7%8.6%8.4%1Mendocino10.3%11.3%10.8%14Napa8.8%9.4%9.4%4Solano11.2%12.3%12%25Sonoma9.4%10.6%10.0%11California12.2%12.8%12.4%--U.S.9.7%9.7%9.5%--

Source: California Employment Development Department and the U.S. Bureau of Labor Statistics