Year	Annual Number
1970	13
1971	3
1972	0
1973	0
1974	76
1975	0
1976	0
1977	0
1978	5
1979	15
1980	0
1981	0
1982	1
1983	0
1984	0
1985	27
1986	7
1987	0
1988	1
1989	4
1990	0
1991	0
1992	2
1993	0
1994	27
1995	8
1996	7
1997	0
1998	0
1999	7
2000	1
2001	2
2002	0
2003	1
2004	3
2005	1
2006	0
2007	2
2008	1