Year	Annual Number
1970	407
1971	51
1972	0
1973	9
1974	0
1975	0
1976	47
1977	0
1978	0
1979	62
1980	40
1981	150
1982	90
1983	0
1984	0
1985	0
1986	13
1987	21
1988	120
1989	16
1990	10
1991	0
1992	0
1993	63
1994	37
1995	69
1996	12
1997	2
1998	0
1999	41
2000	113
2001	0
2002	65
2003	56
2004	115
2005	180
2006	150
2007	218
2008	89