Year	Annual Number
1970	0
1971	0
1972	0
1974	0
1975	0
1976	0
1977	500
1978	0
1979	0
1980	12
1981	0
1982	0
1983	163
1984	0
1985	10
1986	0
1987	90
1988	0
1989	0
1990	200
1991	574
1992	0
1993	0
1994	0
1995	0
1996	0
1997	2329
1998	2461
1999	56
2000	37
2001	25
2002	9
2003	0
2004	0
2005	6
2006	70
2007	119
2008	0