Year	Percent
2004	10.4
2005	9.9
2006	9.6
2007	9
2008	8.6
2009	9
2010	9.8
2011	9.6
2012	8.6
2013	9.7
2014	9.7
2015	9.7
2016	9.1
2017	9.6
2018	10.1
2019	9.5
2020	8.7
2021	10.2