Year 1=low to 6=high 2005 3.0555555555555554 2006 3.0276923076923077 2007 3.0384615384615383 2008 3.038461538461539 2009 3.06268656716418 2010 3.0701492537313437 2011 3.0782608695652187 2012 3.0478873239436615 2013 3.0347222222222223 2014 3.044444444444444 2015 3.0402777777777765 2016 3.033802816901408 2017 3.002777777777778 2018 3.0183098591549293 2019 2.9986301369863018 2020 2.986301369863013 2021 2.984722222222223 2022 2.9513513513513527 2023 2.943243243243244