Year % 2012 17.1362271884126 2013 16.0165072358973 2014 16.4493904253109 2015 16.6257726400782 2016 18.5135000997154 2017 19.7140632983486 2018 19.3807311450659 2019 20.8136663988193 2020 19.0341930056221 2021 15.7823913881667 2022 17.7968726252847