737.18.42. The annual percentage determined for a taxation year of a qualified manufacturing corporation is equal to the total of(a) the proportion of 66.1% that the number of days in the taxation year that precede 1 January 2018 is of the number of days in the taxation year;
(b) the proportion of 65.8% that the number of days in the taxation year that follow 31 December 2017 but precede 1 January 2019 is of the number of days in the taxation year;
(c) the proportion of 65.5% that the number of days in the taxation year that follow 31 December 2018 but precede 1 January 2020 is of the number of days in the taxation year; and
(d) the proportion of 65.2% that the number of days in the taxation year that follow 31 December 2019 is of the number of days in the taxation year.