Year	Percent
1990	9.83
1991	9.88
1992	8.82
1994	8.57
1995	9.05
1996	12.78
1997	11.88
1998	11.44
1999	13
2001	12.35
2002	12.33
2003	11.71
2004	12.2
2005	9.27
2006	8.82
2007	7.9
2008	7.99
2009	8.54
2010	10.1
2011	10.9
2012	10.43
2013	9.26
2014	8.29
2015	9.63
2016	8.61
2017	8.9