On or about September 1, 1998, and each September 1 thereafter, NHTSA will—

(a) Calculate, in accordance with the procedures in appendix E of this part, the Federal medical savings and each State's share of those savings, due to the amount by which the State seat belt use rate for the previous calendar year—

(1) Exceeds the national average seat belt use rate for that calendar year, for each State described in § 1240.10(a)(1) of this part; or

(2) Exceeds the State's base seat belt use rate, for each State described in § 1240.10(a)(2) of this part; and

(b) Notify the States described in § 1240.10(c) of this part of their proposed allocations, which shall be equal to the amount of the Federal medical savings calculated under paragraphs (a)(1) and (a)(2) of this section, as applicable, reduced proportionately across all States if the allocations would exceed the total amount authorized for allocation during the fiscal year.