Year 1=low to 6=high 2005 3 2006 3 2007 2.5 2008 2.5 2009 2.5 2010 2.5 2011 2.5 2012 3 2013 3 2014 3 2015 3 2016 3 2017 3.5 2018 3.5 2019 4 2020 4 2021 3.5 2022 4 2023 4