[With regard to any county which is required to operate on a countywide system of road administration as described in Section 19-2-3, this section shall read as follows:]
On the first Six Hundred Thousand Dollars ($600,000.00) or any part thereof, sixty-six and two-thirds percent (66-2/3%) to the state and thirty-three and one-third percent (33-1/3%) to the county.
Above and exceeding Six Hundred Thousand Dollars ($600,000.00), or any part thereof, ninety percent (90%) to the state and ten percent (10%) to the county through June 30, 1989; eighty-five percent (85%) to the state and fifteen percent (15%) to the county from July 1, 1989, through June 30, 1990; eighty percent (80%) to the state and twenty percent (20%) to the county from July 1, 1990, through June 30, 2015; seventy-nine percent (79%) to the state and twenty-one percent (21%) to the county from July 1, 2015, through June 30, 2016; seventy-eight percent (78%) to the state and twenty-two percent (22%) to the county from July 1, 2016, through June 30, 2017; seventy-seven percent (77%) to the state and twenty-three percent (23%) to the county from July 1, 2017, through June 30, 2018; seventy-six percent (76%) to the state and twenty-four percent (24%) to the county from July 1, 2018, through June 30, 2019; and seventy-four percent (74%) to the state and twenty-six percent (26%) to the county for each fiscal year thereafter.