Year	Annual Number
1970	3
1971	250
1972	0
1973	0
1974	0
1975	0
1976	0
1977	21
1978	2
1979	0
1980	70
1981	70
1982	332
1983	0
1984	0
1985	0
1986	62
1987	173
1988	38
1989	38
1990	61
1991	0
1992	0
1993	80
1994	85
1995	0
1996	0
1997	0
1998	0
1999	74
2000	22
2001	15
2002	23
2003	22
2004	0
2005	0
2006	0
2007	17
2008	40