Year	Annual Number
1970	0
1971	0
1972	60
1973	191
1974	346
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	180
1982	0
1983	0
1984	0
1985	0
1986	0
1987	16
1988	23
1989	22
1990	0
1991	10
1992	87
1993	0
1994	0
1995	10
1996	0
1997	0
1998	23
1999	0
2000	114
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0