Year	Annual Number
1971	0
1972	0
1973	0
1975	14
1977	0
1978	0
1979	70
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	18
1991	773
1992	0
1993	0
1994	0
1995	0
1996	32
1997	100
1998	0
1999	11
2000	24
2001	0
2002	137
2003	200
2004	0
2005	306
2006	184
2007	0
2008	0