Year	1=low to 6=high
2005	3.4
2006	3.4
2007	3.4
2008	3.4
2009	3.4
2010	3.5
2011	3.5
2012	3.5
2013	3.3
2014	3.3
2015	3.3
2016	3.3
2017	3.3
2018	3.2
2019	3.1
2020	3
2021	3
2022	3
2023	2.9