Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	10
1978	0
1979	0
1980	15
1981	0
1982	33
1983	0
1984	10
1985	22
1986	0
1987	0
1988	0
1989	36
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	3
1998	0
1999	0
2000	0
2001	13
2002	0
2003	0
2004	4
2005	2
2006	0
2007	0
2008	3