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