If the claimant is married and filing jointly and the sum of the claimant’s adjusted gross income and his or her spouse’s adjusted gross income is at least $18,000 but less than $19,000 in the year to which the claim relates, an amount that is calculated as follows: a.
(a)#
Calculate the value of a fraction, the denominator of which is $1,000 and the numerator of which is the difference between the married couple’s adjusted gross income and $18,000.
(b)#
Subtract from 1.0 the amount that is calculated under subd. 4. a.
(c)#
Multiply the amount of the married couple’s net income tax liability by the amount that is calculated under subd. 4. b.