Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	15
1976	0
1977	0
1978	0
1979	50
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	1
1992	0
1993	0
1994	600
1995	7
1996	12
1997	4
1998	0
1999	0
2000	0
2001	0
2002	18
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0