1. Adjustments to certain State apportionment amounts Section 104 of title 23, United States Code, is amended by striking subsection (c) and inserting the following: (c) Calculation of amounts (1) State share For fiscal year 2019 and each fiscal year thereafter, the amount for each State of combined apportionments for the national highway performance program under section 119, the surface transportation block grant program under section 133, the highway safety improvement program under section 148, the congestion mitigation and air quality improvement program under section 149, the national highway freight program under section 167, and to carry out section 134 shall be determined as follows: (A) Initial amount The initial amount for each State shall be determined by multiplying the total amount available for apportionment by the share for each State, which shall be equal to the proportion that— (i) the amount of apportionments that the State received for fiscal year 2012; bears to (ii) the amount of those apportionments received by all States for that fiscal year. (B) Adjustments to amounts (i) In general The initial amounts resulting from the calculation under subparagraph (A) shall be adjusted to ensure that, for each State, the amount of combined apportionments for the programs shall not be less than an amount equal to— (I) 95 percent of the applicable percentage; multiplied by (II) the total amount of funds available for apportionment. (ii) Applicable percentage For purposes of this subparagraph, the applicable percentage shall be an amount, expressed as a percentage, equal to the quotient of— (I) the estimated tax payments attributable to highway users in the State that were paid into the Highway Trust Fund (other than the Mass Transit Account) for the most recent fiscal year for which data are available