In this section, “total State service” includes any previous State service. Annual leave accrues as follows, on a pro rata basis: for an employee whose total State service is less than 5 years, at the rate of 10 workdays not to exceed 80 hours, a year; for an employee whose total State service is at least 5 years but less than 10 years, at the rate of 15 workdays not to exceed 120 hours, a year; for an employee whose total State service is at least 10 years but less than 20 years, at the rate of 20 workdays not to exceed 160 hours, a year; and for an employee whose total State service is 20 years or more, at the rate of 25 workdays not to exceed 200 hours, a year.