Year	1=low to 6=high
2005	4
2006	4
2007	3.9
2008	3.8
2009	3.8
2010	3.8
2011	3.9
2012	3.9
2013	3.8
2014	3.7
2015	3.7
2016	3.5
2017	3.5
2018	3.5
2019	4.3
2020	4.3
2021	4.3
2022	4.3
2023	4.3