Year	Annual Number
1970	500
1971	0
1972	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	157
1981	990
1982	0
1983	0
1984	0
1985	1101
1986	0
1987	0
1988	7400
1989	0
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	9
2000	422
2001	429
2002	12
2003	0
2004	0
2005	74
2006	351
2007	0
2008	20