Cal. Gov. Code § 20037.5

Notwithstanding Section 20035, “final compensation” for a state member who has elected to be subject to Section 21353.5, for the purposes of determining any pension or benefit based on service credited under that section, means the highest average annual compensation earnable by the member during the consecutive 36-month period immediately preceding the effective date of his or her retirement, or the date of his or her last separation from state service if earlier, or during any other period of 36 consecutive months during his or her state membership that the member designates on the application for retirement.