Year	Percent
1971	0.4338
1972	0.1207
1973	0.2859
1974	0.4671
1975	0.5281
1976	1.241
1977	0.312
1978	0.4266
1979	3.597
1980	0.2998
1981	0.5424
1982	0.6128
1983	0.3845
1984	0.4639
1985	0.7099
1986	0.9311
1987	0.7818
1988	0.5708
1989	1.134
1990	1.666
1991	0.6121
1992	2.063
1993	0.9266
1994	0.9962
1995	1.702
1996	0.9295
1997	0.7195
1998	0.9378
1999	1.241
2000	1.83
2001	0.734
2002	5.181
2003	3.52
2004	3.291
2005	1.093
2006	4.667
2007	3.275