Every retirement allowance or optional death allowance, including an allowance payable to a survivor of a member, payable to or on account of any member of this system or of a superseded system who has been or was retired for service is hereby increased as follows:
Period during which  | Percentage of increase in  | 
retirement became  | monthly retirement  | 
effective  | allowance  | 
On or prior to June 30, 1967 ........................  | 10%  | 
12 months ended June 30, 1968 ........................  | 8%  | 
12 months ended June 30, 1969 ........................  | 6%  | 
12 months ended June 30, 1970 ........................  | 4%  | 
12 months ended June 30, 1971 ........................  | 2%  | 
In no event shall any allowance be increased by an amount greater than seventy-five dollars ($75) a month. A member with credit for 10 or more years of service in the system shall receive not less than twenty-five dollars ($25) a month.
This section shall not be operative in any county until such time as the board of supervisors shall, by ordinance adopted by a majority vote, make the provisions of this section applicable in such county.
(Added by Stats. 1973, Ch. 298.)