Year 1=low to 6=high 2005 4 2006 4 2007 4 2008 4 2009 4 2010 3.5 2011 3 2012 3 2013 3 2014 3.5 2015 3.5 2016 3.5 2017 3.5 2018 3.5 2019 3.5 2020 3.5 2021 3.5 2022 3.5 2023 3.5