Year	Annual Number
1970	90
1971	0
1972	0
1973	0
1974	1400000
1975	0
1976	200000
1977	3003
1978	0
1979	10000
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	360000
1992	4630
1993	0
1994	0
1995	32000
1996	0
1997	137500
1998	0
1999	50020
2000	0
2001	3801
2002	50020
2003	0
2004	0
2005	0
2006	10020
2007	166700
2008	0