1. For all tax years beginning in a calendar year in which there is a reduction in the rate of tax imposed under section 143.071, there shall be a corresponding and proportional reduction in the rate of tax imposed under sections 148.030, 148.140, and 148.620. The reduced rate shall be the applicable rate in each subsequent calendar year.

2. The reduction specified under subsection 1 of this section shall occur each year there is a reduction in the rate of tax imposed under section 143.071, including a reduction in the rate of tax by operation of another law or by the constitution.