Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	18500
1987	0
1988	0
1989	0
1990	0
1991	1500
1992	4700
1993	0
1994	0
1995	0
1996	0
1997	0
1998	9301
1999	0
2000	5000
2001	5000
2002	2500
2003	200
2004	0
2005	0
2006	0
2007	120000
2008	0