Assessment.

(a) The amount of an assessment will be determined by using the actuarial services described in § 165.5 (relating to administration).

(b) Every carrier, doing the business of workers’ compensation insurance in this Commonwealth, will be assessed, based on a prorata share of the total amount of net-written premiums of workers’ compensation insurance reported as written in the previous calendar year’s annual statement.

(c) The assessment, when necessary, will be billed by December 31 of the year that the actuarial study is completed. (Example: Data from the 2002 calendar year is used, the actuarial study is completed in 2003, then the assessment will be made by December 31, 2003.)

(d) Payment of the assessment, when applicable, is due by March 31 of the year following the assessment.