Year 1=low to 6=high 2005 3.1973684210526314 2006 3.1825 2007 3.1958333333333337 2008 3.18 2009 3.1788617886178865 2010 3.1382113821138216 2011 3.1463414634146343 2012 3.120155038759691 2013 3.143939393939395 2014 3.162791240310078 2015 3.1279073643410857 2016 3.1046511627906983 2017 3.0568181818181817 2018 3.089147286821705 2019 3.0303030075757578 2020 3.0189393939393936 2021 3.0348837209302326 2022 3.0189393863636367 2023 3.022727272727273