California Code, Government Code - GOV § 9356.16

Any person who is a member of the system may also receive credit for state service prior to the date he or she became a member, whether the service was rendered before or after the operative date of this section, provided that he or she makes the contributions required by Section 9357.2, but at the rate of 6 1/2 percent.  If he or she elects to make these contribution with respect to service credited under the Public Employees' Retirement System, his or her accumulated contributions, including accrued interest, under that system shall be transferred to his or her account under this system.  Contributions transferred from the Public Employees' Retirement System shall reduce the contributions otherwise required by this section.

The contribution rate for a person who first commences service and who becomes a member of this system on or after January 1, 1982, shall be 8 percent.