Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	10
1979	0
1980	0
1981	7
1982	54
1983	3
1984	51
1985	0
1986	43
1987	0
1988	0
1989	325
1990	33
1991	27
1992	15
1993	8
1994	0
1995	3
1996	0
1997	10
1998	3
1999	6
2000	5
2001	0
2002	2
2003	235
2004	6
2005	6
2006	25
2007	33
2008	33