Year	Percent
1983	5
1984	10
1985	12
1986	17
1987	21
1988	10
1989	41
1990	43
1991	50
1992	50
1993	50
1994	50
1995	50
1996	55
1997	57
1998	55
1999	70
2000	74
2001	77
2002	81
2003	84
2004	86
2005	87
2006	88
2007	90
2008	90
2009	90
2010	91
2011	90