1. (a) The department shall calculate an annual index factor to be used for the rate to take effect each July 1 beginning in 2018 through July 1, 2024. The department shall determine the index factor before June 1 of each year using the method described in subsection (b).

2. (b) The annual gasoline tax index factor, special fuel index factor, and motor carrier surcharge tax index factor equals the following:

   1. (A) the STEP ONE result; and

   2. (B) the STEP TWO result.

      STEP FOUR: Divide the STEP THREE result by two (2).

   STEP ONE: Divide the annual CPI-U for the year preceding the determination year by the annual CPI-U for the year immediately preceding that year.

   STEP TWO: Divide the annual IPI for the year preceding the determination year by the annual IPI for the year immediately preceding that year.

   STEP THREE: Add:

As added by P.L.218-2017, SEC.37.