Year	Annual Number
1970	0
1971	0
1972	3
1973	59
1974	0
1975	0
1976	0
1977	0
1978	0
1979	53
1980	18
1981	0
1982	0
1983	9
1984	0
1985	32
1986	1
1987	1
1988	0
1989	0
1990	0
1991	0
1992	1
1993	21
1994	0
1995	0
1996	0
1997	25
1998	0
1999	12
2000	0
2001	1
2002	0
2003	17
2004	16
2005	0
2006	0
2007	1
2008	7