(1) For calendar year 2021 and thereafter, the total premium rate shall be based on the family and medical leave insurance account balance ratio as of September 30th of the previous year.

(2) The commissioner shall calculate the account balance ratio by dividing the balance of the family and medical leave insurance account by total covered wages paid by employers and those electing coverage.

(3) For the purposes of this section, "total covered wages" is defined as the total amount of wages paid to employees that are subject to the paid family and medical leave premium from July 1st of the previous calendar year to June 30th of the current calendar year as reported by employers.