Year	Annual Number
1970	0
1971	0
1972	0
1973	60
1974	100
1975	20
1976	0
1977	0
1978	5
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	1
1987	1
1988	0
1989	0
1990	0
1991	0
1992	0
1993	15
1994	0
1995	6
1996	0
1997	0
1998	0
1999	0
2000	1
2001	20
2002	3
2003	12
2004	0
2005	11
2006	0
2007	0
2008	0