Year	1=low to 6=high
2005	3.1
2006	2.9
2007	2.9
2008	2.9
2009	2.8
2010	2.9
2011	3
2012	3
2013	2.9
2014	2.9
2015	2.9
2016	2.9
2017	2.9
2018	2.9
2019	2.7
2020	2.7
2021	2.7
2022	2.8
2023	2.8