Year 1=low to 6=high 2005 2.5 2006 2.5 2007 2.5 2008 2.5 2009 2.5 2010 3 2011 3.5 2012 3.5 2013 3.5 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