Year	1=low to 6=high
2005	2.7
2006	2.6
2007	2.7
2008	2.6
2009	2.6
2010	2.6
2011	2.6
2012	2.6
2013	2.7
2014	2.7
2015	2.8
2016	2.9
2017	2.9
2018	2.9
2019	2.9
2020	2.9
2021	3
2022	3
2023	3