Applicable percentage

In the case of a joint return, the applicable percentage is—

(A) if the adjusted gross income of the taxpayer is not over $30,000, 50 percent,

(B) if the adjusted gross income of the taxpayer is over $30,000 but not over $32,500, 20 percent,

(C) if the adjusted gross income of the taxpayer is over $32,500 but not over $50,000, 10 percent, and

(D) if the adjusted gross income of the taxpayer is over $50,000, zero percent.

In the case of—

(A) a head of household, the applicable percentage shall be determined under paragraph (1) except that such paragraph shall be applied by substituting for each dollar amount therein (as adjusted under paragraph (3)) a dollar amount equal to 75 percent of such dollar amount, and

(B) any taxpayer not described in paragraph (1) or subparagraph (A), the applicable percentage shall be determined under paragraph (1) except that such paragraph shall be applied by substituting for each dollar amount therein (as adjusted under paragraph (3)) a dollar amount equal to 50 percent of such dollar amount.

In the case of any taxable year beginning in a calendar year after 2006, each of the dollar amounts in paragraph (1) shall be increased by an amount equal to—

(A) such dollar amount, multiplied by

(B) the cost-of-living adjustment determined under section 1(f)(3) for the calendar year in which the taxable year begins, determined by substituting “calendar year 2005” for “calendar year 2016” in subparagraph (A)(ii) thereof.

Any increase determined under the preceding sentence shall be rounded to the nearest multiple of $500.