Year % 2011 8.16 2012 8.8 2013 8.69 2014 9.02 2015 9.47 2016 9.78443760400052 2017 9.8335923309073 2018 9.49140928226404 2019 9.93660564443561 2020 9.44471998719333 2021 9.09026312855038