A member under municipal fire member coverage plan 4 shall contribute twelve and eight-tenths percent of salary with the first full pay period in the calendar month in which municipal fire member coverage plan 4 becomes applicable to the member, except that a member whose annual salary is greater than twenty-five thousand dollars ($25,000) shall contribute:

A. beginning July 1, 2021 and continuing through June 30, 2022, fifteen and eight- tenths percent of salary;

B. beginning July 1, 2022 and continuing through June 30, 2023, sixteen and three- tenths percent of salary;

C. beginning July 1, 2023 and continuing through June 30, 2024, sixteen and eight- tenths percent of salary;

D. beginning July 1, 2024 and continuing through June 30, 2025, seventeen and three-tenths percent of salary; and

E. beginning July 1, 2025 and thereafter, seventeen and eight-tenths percent of salary.