Year 1=low to 6=high 2005 3.3583333333333334 2006 3.3455284552845534 2007 3.3821138211382125 2008 3.360975609756098 2009 3.369918699186993 2010 3.357723577235772 2011 3.369047619047618 2012 3.3452380952380953 2013 3.3449612403100777 2014 3.3577234146341453 2015 3.3211381300813 2016 3.2894734210526324 2017 3.2850877192982444 2018 3.267543859649122 2019 3.28205123076923 2020 3.263157894736841 2021 3.2456140263157907 2022 3.2564102051282053 2023 3.2735041794871793