Year	Percent
1996	13.4
1999	19.4
2002	14.5
2003	13.6
2004	12.1
2005	11.7
2006	13.5
2007	12.5
2008	11.7
2009	10.7
2010	9.9
2011	9.2
2012	8.8
2013	8.4
2014	8.3