Looks like it's about 51%:
About Your Plan
Your plan is a defined benefit plan. Under this plan, your retirement benefit is based on your age, service credit and average final compensation at retirement using a formula. For most members in the defined benefit plan, the unreduced benefit replaces approximately 51 percent of the member's average highest salary.
http://www.varetire.org/members/benefits/defined-benefit/plan.asp?pt=p1&pn=vrs