Cal. Gov. Code § 20037
For a state member, or for a local member who is an employee of a contracting agency that is subject to this section, "final compensation" means the highest annual average compensation earnable by a member during any consecutive 36-month period of employment preceding the effective date of his or her retirement or the date of his or her last separation from state service if earlier, including any or all of the period or periods of (a) service required for qualification for membership, or (b) prior service which qualifies for credit under this system, if any, immediately preceding membership, or (c) time prior to entering state service at the compensation earnable by him or her in the position first held by him or her in that service, as may be necessary to complete three consecutive years. For the purposes of this section, periods of service separated by a period of retirement or breaks in service may be aggregated to constitute a period of three consecutive years, if the periods of service are consecutive except for such a period of retirement or breaks. If a break in service did not exceed six months in duration, time included in the break and compensation earnable during that time shall be included in computation of final compensation. If a break in service exceeded six months in duration, the first six months thereof and the compensation earnable during those six months shall be included in computation of final compensation, but time included in the break which is in excess of six months and the compensation earnable during that excess time shall be excluded in computation of final compensation. On and after November 13, 1968, this section shall apply to all contracting agencies and to the employees of those agencies whether or not those agencies have previously elected to be subject to this section, except that this section shall not apply to an employee of a contracting agency which has not elected to be subject to this section whose death occurred or whose retirement was effective prior to November 13, 1968.
Ca. Gov. Code § 20037