Year 1=low to 6=high 2005 2.8499999999999996 2006 2.8499999999999996 2007 2.8499999999999996 2008 2.9 2009 2.9 2010 2.8499999999999996 2011 2.8499999999999996 2012 2.7 2013 2.75 2014 2.7 2015 2.55 2016 2.45 2017 2.25 2018 2.35 2019 2.4 2020 2.45 2021 2.4 2022 2.35 2023 2.3