Year	Percent
1985	12
1986	11
1987	11
1988	14
1989	17
1990	22
1991	22
1992	21
1993	22
1994	25
1995	28
1996	23
1997	21
1998	17
1999	15
2000	11
2001	10
2002	9
2003	13
2004	10
2005	6
2006	8