Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	50
1977	0
1978	0
1979	0
1980	0
1981	0
1982	500
1983	12
1984	1
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	154
1992	14
1993	0
1994	160
1995	0
1996	0
1997	5
1998	7023
1999	70
2000	0
2001	4
2002	1200
2003	1
2004	2
2005	6
2006	1
2007	0
2008	0