Year	Percent
1984	11.72
1985	12.5
1986	22.98
1988	23.2
1989	20.53
1990	17.24
1991	14.51
1992	13.9
1993	13.6
1994	12.8
1995	13.14
1996	13.97
1997	15.27
1998	16.22
2000	14.04
2002	15.59
2003	15.1
2004	16.09
2005	18.16
2006	14.65
2007	12.39
2008	10.55
2009	9.62
2011	9.78
2013	13.03