Year 1=low to 6=high 2005 2.795652173913044 2006 2.7320000000000007 2007 2.724 2008 2.7120000000000006 2009 2.765384615384616 2010 2.7807692307692315 2011 2.8035714285714284 2012 2.7600000000000002 2013 2.7419354838709675 2014 2.7709677419354843 2015 2.75483870967742 2016 2.7483870967741937 2017 2.6843749999999997 2018 2.7064516129032254 2019 2.665625 2020 2.646875 2021 2.5967741935483866 2022 2.553125 2023 2.50625