The chart above comes from a recently-released study on pay premiums by level of education by state. California shows up as having a relatively high premium for college grads and advanced degree grads relative to high school grads. The data are based on median wage & salary adjusted to 2010 dollars for 2006-10. The study groups workers by their broad occupational field: arts & humanities, business & commerce, health, and STEM (science, technology, engineering, math). It is interesting to note that the high premium in California shows up within each of these broad areas as well as for all combined.
To make the chart clearer, click on it. I have marked California with a dark rectangle.
The study was released by a group called the State Higher Education Executive Officers Assn. You can find the study (including a methodology statement) at: