Your ASRS contribution rate actually consists of two main parts: the “Pension and Health Insurance Benefit” rate, which is a pre-tax deduction from your paycheck, and the “Long Term Disability Income Plan” rate, which is a post-tax deduction. If you look at your paystub, the pre-tax deduction is listed as “ASRSRET” while the post-tax deduction is labeled “ASRS LTD.”
Even if you've been a contributing member for years, it's good to check just in case.