Year	%
2000	14.5
2001	14
2002	13.7
2003	13.5
2004	12.9
2005	12.4
2006	12.2
2007	11.7
2008	11.4
2009	10.7
2010	10.5
2011	9.8
2012	9.7
2013	9.6
2014	9.6
2015	9.6
2016	9.5
2017	9.3
2018	9
2019	8.9