producer, or importer thereof. (b) Amount of tax (1) In general The amount of tax imposed by subsection (a) on any taxable carbon substance shall be the applicable amount per ton of the carbon dioxide emissions potential of such substance, as determined by the Secretary in consultation with the Secretary of Energy. (2) Fractional part of ton In the case of a fraction of a ton, the tax imposed by subsection (a) shall be the same fraction of the amount of such tax imposed on a whole ton. (3) Applicable amount (A) In general For purposes of this part, the applicable amount is— (i) for calendar year 2020, $40, (ii) for any calendar year following a year which is not a national emissions target attainment year, the sum of— (I) the product of the amount in effect under this subparagraph for the preceding calendar year and 102.5 percent, and (II) the inflation adjustment amount determined under subparagraph (B), and (iii) for any calendar year following a year which is a national emissions target attainment year, the sum of— (I) the amount in effect under this subparagraph for the preceding calendar year, and (II) the inflation adjustment amount determined under subparagraph (B). (B) Inflation adjustment amount (i) In general The inflation adjustment amount for any calendar year shall be an amount (not less than zero) equal to the product of— (I) the amount determined under subparagraph (A)(ii)(I) or (A)(iii)(I), as applicable, for such year, and (II) the percentage by which the CPI for the preceding calendar year exceeds the CPI for the second preceding calendar year. (ii) CPI Rules similar to the rules of paragraphs (4) and (5) of section 1(f) shall apply for purposes of this paragraph. (C) Rounding The applicable amount under this subsection shall be rounded up to the next whole dollar amount. (D) National emissions target attainment year For purposes of subparagraph (A), a calendar year is a national emissions target attainment year if the level of greenhouse gas emissions in the United States for the calendar year