Year	Percent
1996	11.5
2001	11.4
2002	11.7
2003	11.9
2004	12.4
2005	10.3
2006	13.1
2007	13
2008	13.4
2009	13.4
2010	13.5
2011	13.4
2012	13.3
2013	13.6
2014	13.7
2015	13.7