Year	1=low to 6=high
2005	2.6
2006	2.7
2007	2.6
2008	2.6
2009	2.6
2010	2.6
2011	2.6
2012	2.5
2013	2.5
2014	2.5
2015	2.5
2016	2.5
2017	2.5
2018	2.5
2019	2.7
2020	2.5
2021	2.5
2022	2.7
2023	2.8