The California Department of Finance released an announcement (and data) stating that the San Francisco Bay Area is the fastest growing region in California with a population growth rate of 1.6%. The 2013 report lists 482 cities with 444 having gains in population.
Not surprising is that cities with more open area such as Morgan Hill (2.59%) and Gilroy (2.92%)were a couple of the fastest growing cities in Santa Clara County. Los Altos Hills with a growth of 3.11% is a little more surprising. Of the other Santa Clara County cities Sunnyvale had the greatest growth with 2.31%
Santa Clara County had a population growth rate of 1.6% and San Mateo County had a population growth rate of 1.1%.
http://www.dof.ca.gov/research/demographic/reports/estimates/e-1/