Year 1=low to 6=high 2005 3.1210526315789475 2006 3.0824999999999996 2007 3.1050000000000004 2008 3.1025000000000005 2009 3.117073170731707 2010 3.156097560975611 2011 3.182926829268293 2012 3.1488372093023265 2013 3.125 2014 3.1488372093023256 2015 3.144186046511628 2016 3.1232558139534885 2017 3.0931818181818174 2018 3.127906976744186 2019 3.113636363636363 2020 3.1454545454545455 2021 3.1511627906976742 2022 3.1500000000000004 2023 3.1477272727272734