Year Percent (Units) 2011 0.020 2012 0.014 2013 0.013 2014 0.015 2015 0.017 2016 0.018 2017 0.019 2018 0.019 2019 0.019 2020 0.019 2021 0.018 2022 0.018 2023 0.018 2024 0.018 2025 0.018 2026 0.019 2027 0.019 2028 0.019 2029 0.019