County-level demographic change back to 1990

I’m looking for county-level data (only for California) that would give yearly estimates of race/ethn. changes between 1990 and 2010. Since the ACS only began in the 2000s, I’m not sure if there is any good annual data for this that goes back far enough.

The Census Bureau produces annual estimates of county populations broken down by age, sex, race, and ethnicity, going back to 1990. You can find the data and documentation through this Census Bureau webpage. (We don’t currently redistribute these data through any IPUMS site.)