Longevity pay shall be paid as follows:

(1) One percent (1%) of base salary after the equivalent of five (5) years of full time County service (10,400 hours).

(2) An additional one and one-half percent (1.5%) of base salary (for a total of two and one half percent (2.5%)) after the equivalent of ten (10) years of full time County service (20,800 hours)

(3) An additional one and one-half percent (1.5%) of base salary (for a total of four percent (4%)) after the equivalent of twenty (20) years of full time County service (41,600 hours)

(4) An additional two percent (2%) of base salary (for a total of six percent (6%)) after the equivalent of twenty-five (25) years of full time County service (52,000 hours)