My hometown newspaper, the San Jose Mercury News, just published an interesting article (with accompanying video) about the high rate of citizenship among California's Mexican population. See:
Census figures show 70 percent of California's Mexican population are U.S. citizens 11/04/2007
Summary: For the first time in the most current wave of immigration, U.S. Census figures show that 70 percent of California's Mexican population are U.S. citizens, blunting widespread belief the state is overrun by illegal immigrants.
[VIDEO] A ceremony for 450 new U.S. citizens at the Heritage Theatre in Campbell, Calif., on Wed., October 24, 2007.