Year 1=low to 6=high 2005 3.4109090909090902 2006 3.396875000000001 2007 3.417767295597483 2008 3.415094339622643 2009 3.4260802469135805 2010 3.4239197530864196 2011 3.402272727272728 2012 3.393601190476191 2013 3.376169590643275 2014 3.341667307692308 2015 3.3262824358974368 2016 3.30561238095238 2017 3.301190476190476 2018 3.2906462585034015 2019 3.30483332 2020 3.2920138888888886 2021 3.2852429583333334 2022 3.2739795510204077 2023 3.2802721020408168