Year	Percent
1976	10.95
1977	10.91
1978	9.42
1979	7.44
1981	9.95
1982	10.41
1983	12.82
1984	11.73
1985	12.36
1986	10.37
1987	9.82
1988	8.82
1990	8.88
1991	11.36
1992	11.08
1993	11.63
1995	9.24
1996	9.97
1997	10.28
1998	10.08
1999	8.29
2000	6.67
2002	8.94
2003	9.53
2004	7.66
2005	9.11
2006	9.57
2007	8.96
2008	9.32