the age of the older spouse shall be taken into account under clause (i). (iii) Indexing In the case of any taxable year beginning after calendar year 2021, the initial and final percentages contained in clause (i) shall be adjusted to reflect— (I) the excess (if any) of the rate of premium growth for the period beginning with calendar year 2013 and ending with calendar year 2021, over the rate of income growth for such period, and (II) in addition to any adjustment under subclause (I), the excess (if any) of the rate of premium growth for calendar year 2021, over the rate of growth in the consumer price index for calendar year 2021. (iv) Failsafe Clause (iii)(II) shall apply only if the aggregate amount of premium tax credits under this section and cost-sharing reductions under section 1402 of the Patient Protection and Affordable Care Act for the preceding calendar year exceeds an amount equal to 0.504 percent of the gross domestic product for such calendar year. . (b) Expansion of eligibility Section 36B of the Internal Revenue Code of 1986 is amended— (1) in subsection (c)(1)(A), by striking 400 and inserting 600