Year 1=low to 6=high 2005 3.121944444444444 2006 3.083333333333334 2007 3.1067708333333335 2008 3.103125 2009 3.118434343434344 2010 3.1159090909090916 2011 3.1396464646464644 2012 3.1093137254901966 2013 3.1063725490196075 2014 3.1224755555555554 2015 3.0944452525252535 2016 3.059343535353536 2017 3.0129901960784315 2018 3.042171717171717 2019 3.0088235196078434 2020 3.015441176470589 2021 3.0356060606060606 2022 3.021568647058824 2023 3.034558882352942