July 1, 2017 – 18.75 cents per gallon July 1, 2018 – 20.75 cents per gallon July 1, 2019 – 22.75 cents per gallon July 1, 2020 – 24.75 cents per gallon July 1, 2021 – 26.75 cents per gallon July 1, 2022 – 28.75