Year 1=low to 6=high 2005 3.277272727272728 2006 3.2284722222222215 2007 3.2295454545454545 2008 3.2818181818181817 2009 3.3318181818181825 2010 3.3515151515151516 2011 3.280769230769231 2012 3.2357142857142853 2013 3.2022222222222223 2014 3.203333333333333 2015 3.1838891111111116 2016 3.1369042857142864 2017 3.119047619047619 2018 3.1214285714285714 2019 3.1029761428571425 2020 3.0940476190476183 2021 3.060118928571429 2022 3.0511903571428576 2023 3.034523714285715