Excuse me? Your evidence would be?
Personal observation driving up to San Francisco on Route 1, trying to find a vacant space in a campground along the way, getting stuck a traffic jam in Yosemite, driving through new housing developments east of Bakersfield last summer as I went to visit a friend, encountering bumper to bumper traffic at the 9000 foot level in the Sierras east of Bishop (or for that matter trying to find a hotel room in Bishop itself, two years ago). Between 1950 and 2000, California's population grew by more than 24 million and is expected to hit 60 million by 2050. How many more examples do you need? What's your contention? That California's population is going down?