For the first time since the Gold Rush. LA Times story here. Interestingly during the 2000-2009 Census period, California LOST 1,509,708 people due to internal em/immigration. Only international immigration kept the population-due-to-em/immigration above water (by about 1% of the state's total population.) Many of these are Latin American, but a large number of high-skill well-to-do Asian immigrants are coming on 747s.
Suggested research*: relationship between proportion of ethnic populations who are legal immigrants or permanent legal residents vs. citizens, and per capita income in those populations; relationship between prevalence of international immigrants or incidence of international immigration in last decade and per capita income change. Also, distribution within California by country of origin of new international immigrants.
*"Suggested research" translates to "someone else do the work, I'm not a frickin demographics grad student over here".