Year	Percent
1987	8.701
1988	7.004
1989	5.965
1990	7.478
1991	7.458
1992	7.458
1993	7.459
1994	10.23
1995	12.27
1996	12.29
1997	7.61
1998	14.45
1999	10.54
2000	10.22
2001	14.29
2002	16.78
2003	12.5
2004	8.509
2005	13.81
2006	16.84
2007	24.05