While much is made of the unemployment number, a better measure of the jobs picture is the Bureau of Labor's U-6 index, which includes those who are unemployed, discouraged workers, and those who are working part time. For purposes of being considered as "employed" you can work as little as one hour a week, but that would still make you "underemployed" if you are seeking additional hours.
For the record, California's U-6 20.3% unemployment rate is number two in the nation. Only Nevada at 22.1% has a higher U-6. North Dakota has the lowest U-6 at only 6.1%.
You can find a great chart of the various categories of unemployment at: http://www.bls.gov/lau/stalt.htm