Year	Annual Number
1970	0
1971	90000
1972	0
1973	0
1974	0
1975	0
1976	0
1977	16820
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	323300
1985	0
1986	30820
1987	0
1988	0
1989	0
1990	0
1991	0
1992	38000
1993	0
1994	0
1995	0
1996	0
1997	2254
1998	0
1999	0
2000	0
2001	2402
2002	0
2003	0
2004	0
2005	157
2006	0
2007	0
2008	0