Year % 2008 2.82208199288245 2009 4.08301602290229 2010 4.70497582133693 2011 4.53797781890379 2012 4.92137936955479 2013 4.79348889261062 2014 4.61948181975495 2015 4.16510529138445 2016 3.93108996669006 2017 3.83219672759303 2018 3.86657827897154 2019 3.81150994513216 2020 3.71722963023515 2021 2.85023106835435