Year % 2010 18.9831395127209 2011 16.4201614795865 2012 15.43857707742 2013 17.4021611148596 2014 13.7721739573005 2015 13.7727530286221 2016 13.7464547087424 2017 13.9688200493382 2018 13.9287751283879 2019 13.5502449414145 2020 14.2124841791752 2021 14.4436220823237 2022 14.9234836486379