(2) “Average annual retail price” means the 12-month average retail price per gallon of motor fuel purchased in the State determined in accordance with subsection (d) of this section.

(3) “Sales and use tax equivalent rate” means the per gallon tax rate calculated based on a percentage of the average annual retail price of motor fuel in accordance with subsection (e) of this section.

(b) On or before December 1, 2015, June 1, 2016, and June 1 of each subsequent year, the Comptroller shall determine and announce:

(1) the average annual retail price of motor fuel; and

(2) the sales and use tax equivalent rate effective on the first day of the following month.

(c) (1) The sales and use tax equivalent rate shall be added to the motor fuel tax rates specified in § 9-305(a)(2), (3), and (5) of this subtitle and collected in the same manner as the motor fuel tax.

(2) Except as otherwise expressly provided by law, all references to the motor fuel tax in State law and regulations apply to the sales and use tax equivalent rate imposed under this section.

(d) The Comptroller shall determine the average annual retail price of motor fuel:

(1) using data compiled by the Oil Price Information Service or another generally recognized and reliable source of information; and

(2) based on prices for regular unleaded motor fuel, excluding federal and State taxes, reported during the 12 months ending on the last day of the second immediately preceding month.

(e) The Comptroller shall determine the sales and use tax equivalent rate by:

(1) multiplying the average annual retail price by the percentage rate specified in subsection (f) of this section; and

(2) rounding the product to the nearest tenth of a cent.

(f) The percentage rate used to calculate the sales and use tax equivalent rate shall be:

(1) 4% for the determination made on December 1, 2015; and

(2) 5% for the determination made on June 1, 2016, and June 1 of each subsequent year.

(g) The Comptroller shall require any person possessing tax-paid motor fuel for sale at the start of business on the date of an increase in the sales and use tax equivalent rate under this section to compile and file an inventory of the motor fuel held at the close of business on the immediately preceding date and remit within 30 days any additional tax that is due on the motor fuel under this section.