Year 1=low to 6=high 2005 3 2006 2.5 2007 2 2008 2 2009 2 2010 2 2011 2 2012 2 2013 2 2014 2.5 2015 2 2016 2 2017 1.5 2018 1.5 2019 1.5 2020 1.5 2021 1.5 2022 2 2023 1.5