Year	Percent
1993	13.6
1995	13.2
1996	13.3
2004	12.3
2005	11.3
2006	11.7
2007	11
2008	11.3
2009	12.3
2010	12.3
2011	12.1
2012	12.2
2013	12.2
2014	12.3
2015	12.3