Year	1=low to 6=high
2005	2.5
2006	3
2007	3
2008	3
2009	3
2010	3
2011	3
2012	3
2013	3
2014	3
2015	3
2016	3
2017	3
2018	3
2019	3
2020	3.5
2021	3.5
2022	4
2023	4