California Code, Government Code - GOV § 9359.16

Notwithstanding the provisions of Section 9359, a member of this system, other than a legislative statutory officer, who is under age 60 and who is credited with 15 or more, but less than 20 years of service shall be retired upon his or her written application therefor to the Board of Administration, and thereafter shall receive for life the retirement allowance provided by this section.  The allowance shall be equal to the retirement allowance that he or she would receive for that service upon retirement at age 60 reduced by 2 percent for each year by which the member's age at the time of retirement is below age 60.