Year 1=low to 6=high 2005 3.15 2006 3.1199999999999997 2007 3.1624999999999996 2008 3.2249999999999996 2009 3.233333333333333 2010 3.2444444444444445 2011 3.2875 2012 3.3624999999999994 2013 3.3749999999999996 2014 3.2199999999999998 2015 3.2 2016 3.1799999999999997 2017 3.2 2018 3.2 2019 3.2 2020 3.175 2021 3.3000000000000003 2022 3.275 2023 3.325