Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	137
1983	0
1984	0
1985	0
1986	0
1987	29
1988	0
1989	275
1990	23
1991	32
1992	0
1993	0
1994	21
1995	0
1996	111
1997	0
1998	0
1999	0
2000	0
2001	0
2002	31
2003	41
2004	33
2005	0
2006	174
2007	216
2008	0