http://en.wikipedia.org/wiki/California_Proposition_13_%281978%29Section 1. (a) The maximum amount of any ad valorem tax on real property shall not exceed one percent (1%) of the full cash value of such property. The one percent (1%) tax to be collected by the counties and apportioned according to law to the districts within the counties.
The proposition decreased property taxes by assessing property values at their 1975 value and restricted annual increases of assessed value of real property to an inflation factor, not to exceed 2% per year.