Year	Annual Number
1970	215
1971	0
1972	0
1973	0
1974	0
1975	60
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	108
1992	0
1993	0
1994	2
1995	2
1996	0
1997	20
1998	31
1999	34
2000	9
2001	7
2002	9
2003	3
2004	10
2005	97
2006	51
2007	12
2008	5