Year	Percent
1996	57
2001	64.9
2002	62
2003	56.3
2004	52
2005	51.6
2006	35.4
2007	24
2008	22.1
2009	22.7
2010	18.1
2011	9
2012	8.9
2013	5.6
2014	6.4
2015	7.7