Year	%
2000	15.5
2001	15.3
2002	15.4
2003	15.3
2004	15.4
2005	15.4
2006	15.9
2007	15.6
2008	15.5
2009	14.9
2010	14.2
2011	14.2
2012	13.6
2013	13.3
2014	12.8
2015	13.2
2016	12.8
2017	11.9
2018	11.8
2019	11.7