Year	1=low to 6=high
2005	3.2
2006	3.2
2007	3.4
2008	3.5
2009	3.4
2010	3.4
2011	3.5
2012	3.5
2013	3.6
2014	3.5
2015	3.4
2016	3.4
2017	3.4
2018	3.4
2019	3.3