Year	Annual Number
1970	0
1971	0
1972	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	210
1981	0
1982	0
1983	5868
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	4694
1991	0
1992	226300
1993	0
1994	0
1995	0
1996	0
1997	27840
1998	2809
1999	0
2000	18590
2001	618
2002	2045
2003	24290
2004	0
2005	0
2006	5719
2007	7625
2008	373