Year Percent change (Units) 2015 13.129 2016 12.389 2017 -4.778 2018 2.285 2019 3.906 2020 -23.584 2021 -16.197 2022 31.405 2023 6.731 2024 4.033 2025 6.198 2026 -4.621 2027 0.241 2028 -1.875 2029 1.693