That means more demand for office space." San Francisco's tight market For perspective, it helps to consider the San Francisco market. The office sector ended the third quarter with a 6 percent vacancy and ?a record high annual rent of ?$66.71 per square foot, according ?to Cushman & Wakefield. In contrast, Sonoma County's monthly rates would translate into annual rates of roughly ?$20 to $30 per square foot for Class A space, the top tier in the market. The brokerage reported that ?1.4 million square feet of new office space is expected to be completed in San Francisco in the current quarter, with 96 percent of the space already leased. The tech boom is fueling the growth, with computer systems design jobs in San Francisco and the Peninsula expected to overtake the number of workers in the financial services sector by early next year, Cushman & Wakefield reported.