Year	Percent
1971	0.00956
1972	2.068
1973	2.816
1974	5.367
1975	6.137
1976	5.992
1977	4.887
1978	2.241
1979	1.96
1980	5.117
1981	4.05
1982	4.854
1983	4.52
1984	5.5
1985	8.321
1986	10.81
1987	6.281
1988	5.154
1989	5.004
1990	5.386
1991	8.056
1992	8.777
1993	6.619
1994	10.83
1995	10.6
1996	7.3
1997	11.35
1998	12.41
1999	7.779
2000	15.01
2001	14.13
2002	7.923
2003	10.27
2004	9.318
2005	8.369
2006	8.755
2007	9.937