(a) For purposes of determining the amount of annual compensation that a county shall pay to a county commissioner, the chair of a county commission, a judge of probate, a sheriff, a tax assessor, a tax collector, a revenue commissioner, a license commissioner, or an elected assistant tax assessor or collector, the 67 counties of the state shall be placed in categories based on population according to the 1990 federal decennial census.
(b) The population categories of counties are as follows:
(1) CATEGORY 1. Population of 450,000 or greater.
(2) CATEGORY 2. Population from 350,001 to 449,999.
(3) CATEGORY 3. Population from 200,001 to 350,000.
(4) CATEGORY 4. Population from 50,001 to 200,000.
(5) CATEGORY 5. Population from 19,000 to 50,000.
(6) CATEGORY 6. Population of less than 19,000.