W. Va. Code § 18-7A-26a
Annuitants whose annuities were approved by the retirement board on or before December eighteen, one thousand nine hundred sixty-two, shall, upon written application, receive in addition to such approved annuities a monthly allowance computed as follows: The annuitant's years of service shall be multiplied by thirty dollars and this product shall then be divided by his monthly retirement allowance, as computed prior to the above-stated date, excluding any portion of said allowance which is based on voluntary deposits of the annuitant.
In addition thereto, beginning July one, one thousand nine hundred sixty-five, each annuitant under the provisions of this section shall receive a monthly amount equal to seventy-six cents multiplied by his total service credit.
W. Va. Code § 18-7A-26a