Year	Percent
1973	0.9333
1974	3.654
1975	3.192
1976	4.216
1977	5.757
1978	2.848
1979	2.848
1980	1.933
1981	0.3563
1982	2.204
1984	1.117
1985	0.2757
1986	0.08078
1988	0.4409
1989	4.349
1990	1.092
1991	1.122
1992	7.168
1993	3.359
1994	6.206
1995	1.865
1996	3.502
1997	4.63
1998	7.28
1999	13.7
2000	7.917
2001	8.936
2002	9.252
2003	6.692
2004	5.547
2005	2.94
2006	2.627
2007	4.908