Year	Annual Number
1970	0
1971	0
1972	0
1973	500
1974	0
1975	0
1976	0
1977	0
1978	2
1979	20
1980	0
1981	0
1982	77
1983	45
1984	0
1985	0
1986	0
1987	5
1988	0
1989	12
1990	0
1991	0
1992	0
1993	0
1994	10
1995	0
1996	1
1997	5
1998	0
1999	0
2000	24
2001	0
2002	6
2003	0
2004	0
2005	0
2006	0
2007	5
2008	0