Year	1=low to 6=high
2005	2.6
2006	2.6
2007	2.6
2008	2.6
2009	2.6
2010	2.6
2011	2.6
2012	2.3
2013	2.2
2014	2.2
2015	2.2
2016	2.2
2017	2
2018	2
2019	2
2020	2
2021	2.1
2022	2.1
2023	2.1