Year 1=low to 6=high 2005 3.15563063063063 2006 3.153378378378379 2007 3.1772522522522526 2008 3.1621621621621627 2009 3.176754385964912 2010 3.180921052631579 2011 3.2046052631578954 2012 3.1739316239316246 2013 3.170940170940171 2014 3.186404561403509 2015 3.172149824561403 2016 3.136842105263159 2017 3.1017094017094022 2018 3.1285087719298246 2019 3.1 2020 3.1091880341880347 2021 3.115598307692308 2022 3.1279914871794867 2023 3.139743641025641