Year 1=low to 6=high 2005 3.236842105263158 2006 3.225 2007 3.2375 2008 3.2125 2009 3.2560975609756095 2010 3.341463414634146 2011 3.3780487804878048 2012 3.313953488372093 2013 3.2954545454545454 2014 3.2906976744186047 2015 3.244186046511628 2016 3.2209302325581395 2017 3.215909090909091 2018 3.255813953488372 2019 3.272727272727273 2020 3.3068181818181817 2021 3.313953488372093 2022 3.3295454545454546 2023 3.2954545454545454