Year 1=low to 6=high 2005 5 2006 5 2007 5 2008 5 2009 5 2010 3.5 2011 3 2012 2.5 2013 2.5 2014 2 2015 2 2016 2 2017 2.5 2018 2.5 2019 2.5 2020 2.5 2021 2.5 2022 2.5 2023 2.5