Year	1=low to 6=high
2005	4
2006	3.7
2007	4
2008	4.1
2009	4.1
2010	4.1
2011	4.1
2012	4.1
2013	4.1
2014	4.1
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