Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	4700
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	256
1982	0
1983	24
1984	4
1985	5
1986	0
1987	0
1988	0
1989	0
1990	22
1991	300
1992	40
1993	0
1994	0
1995	0
1996	0
1997	50
1998	1
1999	0
2000	0
2001	12
2002	36
2003	0
2004	24
2005	73340
2006	0
2007	0
2008	166