Year % 2006 10.8041599222222 2007 10.5510481523038 2008 9.98901352284579 2009 10.9766450308146 2010 11.0398987608935 2011 9.81080381518199 2012 9.90035884746328 2013 10.520099018866 2014 10.8937565287826 2015 10.4058225644923 2016 9.60664701973665 2017 9.48812259528097 2018 8.97292567041423 2019 9.14083475915223 2020 8.19451484269313 2021 7.61928566776367 2022 7.83172030290501 2023 7.5285150596832