Year	Annual Number
1970	0
1971	0
1972	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	3
1983	0
1984	0
1985	0
1986	27
1987	0
1988	0
1989	156
1990	197
1991	100
1992	50
1993	0
1994	0
1995	0
1996	20
1997	0
1998	30
1999	137
2000	259
2001	14
2002	0
2003	35
2004	3
2005	21
2006	192
2007	103
2008	28