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