Year	Annual Number
1970	35
1971	0
1972	0
1973	38
1974	0
1975	0
1976	0
1977	0
1978	1
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	33
1988	0
1989	0
1990	6
1991	0
1992	0
1993	8
1994	3
1995	0
1996	0
1997	22
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	1
2007	0
2008	0