Year	%
2000	15.3
2001	14.4
2002	15.3
2003	15.1
2004	14.3
2005	13.5
2006	13.3
2007	13.5
2008	13.2
2009	12.8
2010	11.5
2011	10.5
2012	9.7
2013	9
2014	8.8
2015	8.2
2016	8.1
2017	8
2018	8.1
2019	8