Year	Annual Number
1970	0
1971	0
1972	0
1973	21
1974	11
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	43
1982	37
1983	0
1984	54
1985	26
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	21
1993	22
1994	40
1995	0
1996	4
1997	4
1998	0
1999	12
2000	44
2001	921
2002	48
2003	41
2004	22
2005	12
2006	1
2007	82
2008	89