Year	Annual Number
1970	0
1971	0
1972	0
1974	0
1975	0
1976	150
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	60
1988	2770
1989	0
1990	0
1991	12
1992	0
1993	0
1994	0
1995	0
1996	700
1997	0
1998	3119
1999	357
2000	186
2001	0
2002	49
2003	27
2004	98
2005	650
2006	1142
2007	584
2008	15