Year	Percent
1983	9
1984	9
1985	10
1986	11
1987	9
1988	11
1989	10
1990	9
1991	9
1992	7
1993	6
1994	7
1995	18
1996	15
1997	9
1998	17
1999	17
2000	10
2001	12
2002	12
2003	16
2004	13
2005	10
2006	8