(a) Normal retirement. The normal retirement benefit shall be two per cent times the number of years of full-time credited service and a proportional fraction of two per cent times the number of years of credited service at less than full-time multiplied by average annual salary. In no event, however, shall such benefit exceed seventy-five per cent of such salary or be less than three thousand six hundred dollars.
(b) Proratable retirement. The proratable retirement benefit shall be computed as follows: Average annual salary multiplied by (1) number of years of credited service in the public schools of Connecticut multiplied by the applicable percentage based on age and service as determined from the table below, and (2) number of years of all additional credited service not used in subdivision (1) of this subsection multiplied by one per cent.