(a) Except as otherwise provided in this part, of the new light duty motor vehicles acquired annually for State government fleets, including agencies thereof but excluding municipal fleets, the following percentages shall be alternative fueled vehicles for the following model years;

(1) 10 percent for model year 1997;

(2) 15 percent for model year 1998;

(3) 25 percent for model year 1999;

(4) 50 percent for model year 2000; and

(5) 75 percent for model year 2001 and thereafter.

(b) Each State shall calculate its alternative fueled vehicle acquisition requirements for the State government fleets, including agencies thereof, by applying the alternative fueled vehicle acquisition percentages for each model year to the total number of new light duty motor vehicles to be acquired during that model year for those fleets.

(c) If the calculation performed under paragraph (b) of this section produces a number that requires the acquisition of a partial vehicle, an adjustment to the acquisition number will be made by rounding the number of vehicles down the next whole number if the fraction is less than one half and by rounding the number of vehicles up to the next whole number if the fraction is equal to or greater than one half.

(d) A State fleet that first becomes subject to this part after model year 1997 shall acquire alternative fueled vehicles in the next model year at the percentage applicable to that model year according to the schedule in paragraph (a) of this section, unless the State is granted an exemption or reduction of the acquisition percentage pursuant to the procedures and criteria in section 490.204.