Year	Percent
1973	1.648
1974	0.1359
1975	9.676
1976	0.6327
1977	0.03834
1978	0.03838
1979	0.1181
1980	0.0855
1981	0.04778
1982	0.4481
1983	0.2063
1984	0.1607
1985	2.653
1986	0.9872
1987	3.932
1988	2.537
1989	0.7603
1990	11.85
1991	0.7776
1992	1.547
1993	6.218
1994	5.651
1995	4.104
1996	4.056
1997	22.6
1998	4.218
1999	24.57
2000	14.78
2001	2.562
2002	4.299
2003	6.59
2004	11.12
2005	11.44
2006	6.736
2007	7.694