Year	Annual Number
1970	0
1971	0
1972	653
1973	3
1974	94
1975	0
1976	18
1977	24
1978	53
1979	0
1980	2
1981	353
1982	33
1983	11
1984	0
1985	68
1986	3
1987	0
1988	0
1989	44
1990	176
1991	70
1992	79
1993	53
1994	62
1995	476
1996	0
1997	18
1998	0
1999	164
2000	55
2001	43
2002	90
2003	0
2004	49
2005	5
2006	36
2007	40
2008	116