Year	%
2000	13.1
2001	13.4
2002	13.5
2003	13.4
2004	13.4
2005	12.7
2006	12.5
2007	11.8
2008	11.2
2009	10.8
2010	10.6
2011	10
2012	10.1
2013	9.8
2014	10
2015	9.7
2016	9.2
2017	8.8
2018	8.3
2019	8.2