The city has elected and does elect to participate as a member of the statewide city employees’ retirement system for pension, relief, disability and retirement for the employees of the city as provided by Chapter 41.44 RCW. All employees and officers of the city shall be included in the system except members of the Auburn fire department; provided, that no elective official shall be included unless the official so elects and files a written notice of such election with the board of trustees of the pension system with the city clerk. (1957 code § 1.25.010.)