Year	Percent
1994	11.02
1995	10.19
1996	9.59
1997	9.3
1998	8.76
1999	8.73
2000	6.65
2001	6.49
2002	13.7
2003	13.39
2004	13.64
2005	13.52
2006	13.48
2007	22.55
2008	17.77
2009	19.94
2010	20.59
2011	18.86
2012	17.26
2013	16.81
2014	17.44
2015	18.57
2017	19.35