Most listings are in the $0's per square foot per year. The California region is going through a decrease in rates. In the last 3 months, the median rate decreased $21 per sqft per year. That's a 100% decline in rent.
In the last 90 days, 0 listings have been made available, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. About NaN% of the listings in the California are subleases, so you will probably need to consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around sqft. Most buildings in this region were built in 2002 and are Class A.