Sec. 4. (a) The nine (9) classes of the several judicial circuits of the state as set out in this chapter are based on a unit factor system. The factors are determined by the relations of the judicial circuit to the state as established and certified to each county auditor by the state board of accounts not later than June 20 of any calendar year. They are as follows:
(1) Population.
(2) Gross assessed valuation as shown by the last preceding gross assessed valuation as certified by the various counties to the auditor of the state in the calendar year in which the calculation is made.
(b) The factors for each of the nine (9) classes set out in this chapter shall be obtained as follows:
(1) The population of each judicial circuit shall be divided by the population of the entire state.
(2) The gross assessed valuation of each judicial circuit shall be divided by the gross assessed valuation of the entire state.
(3) The two (2) results thus obtained shall be added together and the sum thus obtained for each judicial circuit shall be divided by two (2).
(4) The final result so obtained, multiplied by one hundred (100), shall determine the classification of each judicial circuit according to the following schedule: