Year	1=low to 6=high
2005	3.9
2006	3.9
2007	3.9
2008	3.9
2009	3.9
2010	3.8
2011	3.8
2012	3.8
2013	3.9
2014	3.9
2015	3.9
2016	3.9
2017	3.9
2018	3.9
2019	3.9
2020	3.9
2021	3.9
2022	3.9
2023	3.9