N.Y.C. Admin. Code § 11-643.2: § 11-643.2 Computation of tax for taxable years beginning in nineteen hundred seventy-three and ending in nineteen hundred seventy-four.

For each taxable year beginning in nineteen hundred seventy-three and ending in nineteen hundred seventy-four, two tentative taxes shall be computed, the first as provided in section 11-643 and the second as provided in section 11-643.1 of this part, and the tax for each such year shall be the sum of that proportion of each tentative tax which the number of days in nineteen hundred seventy-three and the number of days in nineteen hundred seventy-four, respectively, which fall within the taxable year, bears to the number of days in the entire taxable year.