Year	%
1999	11.6
2001	11.9
2002	12
2003	12.4
2004	11.5
2005	11.8
2006	13.1
2007	12.8
2008	13.1
2009	13.5
2010	13
2011	13.2
2012	13.2
2013	12.9
2014	12.7
2015	12.6
2016	12.1
2017	12.4