Year 1=low to 6=high 2005 3.283783783783783 2006 3.2945945945945945 2007 3.3558558558558564 2008 3.364864864864865 2009 3.3859649122807016 2010 3.3815789473684212 2011 3.403508771929825 2012 3.38034188034188 2013 3.3547008547008543 2014 3.3377189473684212 2015 3.2763157017543856 2016 3.18859649122807 2017 3.1367521367521367 2018 3.1491228070175437 2019 3.1367521367521367 2020 3.1495726495726495 2021 3.1623931538461534 2022 3.158119692307692 2023 3.18803417948718