B. Employer matching contributions, if any, and the earnings on employer matching contributions are vested and the employee is entitled to receive employer matching contributions and earnings on those contributions as follows:

1. 1. If the employee has less than one year of credited service in an eligible group, zero per cent.
2. 2. If the employee has at least one year but less than two years of credited service in an eligible group, twenty per cent.
3. 3. If the employee has at least two years but less than three years of credited service in an eligible group, forty per cent.
4. 4. If the employee has at least three years but less than four years of credited service in an eligible group, sixty per cent.
5. 5. If the employee has at least four years but less than five years of credited service in an eligible group, eighty per cent.
6. 6. If the employee has at least five years of credited service in an eligible group, one hundred per cent.