Any county official as herein defined may after July 1, 1968, retire from office and be paid retirement benefits provided said county official has attained the age of fifty-five (55) years and presents satisfactory evidence of at least twelve (12) years service but less than twenty-four (24) years service, said retirement benefits to be paid as follows: 12 years service — 1/2 of full retirement benefits 13 years service — 13/24 of full retirement benefits 14 years service — 7/12 of full retirement benefits 15 years service — 5/8 of full retirement benefits 16 years service — 2/3 of full retirement benefits 17 years service — 17/24 of full retirement benefits 18 years service — 3/4 of full retirement benefits 19 years service — 19/24 of full retirement benefits 20 years service — 5/6 of full retirement benefits 21 years service — 7/8 of full retirement benefits 22 years service — 11/12 of full retirement benefits 23 years service — 23/24 of full retirement benefits.

12 years service — 1/2 of full retirement benefits 13 years service — 13/24 of full retirement benefits 14 years service — 7/12 of full retirement benefits 15 years service — 5/8 of full retirement benefits 16 years service — 2/3 of full retirement benefits 17 years service — 17/24 of full retirement benefits 18 years service — 3/4 of full retirement benefits 19 years service — 19/24 of full retirement benefits 20 years service — 5/6 of full retirement benefits 21 years service — 7/8 of full retirement benefits 22 years service — 11/12 of full retirement benefits 23 years service — 23/24 of full retirement benefits.