Year	1=low to 6=high
2005	3.9
2006	3.9
2007	3.9
2008	4
2009	4
2010	4
2011	4.2
2012	4.2
2013	4.3
2014	4.3
2015	4.3
2016	4.3
2017	4.3
2018	4.3
2019	4.4
2020	4.4
2021	4.4
2022	4.4
2023	4.5