Any member retiring under the provisions of the System shall have the opportunity to elect to defer the commencement of retirement benefits by one-year periods by an election in writing submitted to the Board not later than thirty (30) days prior to the member's normal retirement date or the member's actual retirement date, whichever is later. Such elections may be made successively but may not be deferred later than age sixty-five (65). Retirement benefits payable to members electing to defer the commencement of payments shall be increased by five percent (5%) of the amount that would otherwise be paid for each year payments are deferred.
Okla. Stat. tit. 47, § 2-308.1