Year	Percent
1985	9
1986	8
1987	8
1988	10
1989	10
1990	11
1991	11
1992	12
1993	12
1994	8
1995	9
1996	8
1997	8
1998	7
1999	8
2000	7
2001	7
2002	6
2003	6
2004	6
2005	6
2006	5