Cal. Rev. & Tax. Code § 987

The assessment of lands owned by a local government that are located outside its boundaries shall be as specified in Section ll of Article XIII of the Constitution. The State Board of Equalization shall compute for each assessment year, on or before the lien date of that assessment year, the ratio to be applied to land assessed as of the 1966 lien date and the ratio to be applied to land assessed as of the 1967 lien date in the manner specified in subdivision (b) of Section 11 of Article XIII of the Constitution.