Section 20132 Of Article 2. Powers And Duties Of The Board From California Government Code >> Division 5. >> Title 2. >> Part 3. >> Chapter 2. >> Article 2.

. (a) Upon the basis of any investigation, valuation, or determination, or all of these, the board shall adopt mortality, service and other tables and annual and actuarial interest rates it deems necessary.
  (b) A change in interest rate adopted by the board shall not apply to any election of a member to deposit or redeposit contributions, including interest, filed prior to the date the change was placed into effect.