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	156
1983	0
1984	0
1985	0
1986	367
1987	0
1988	0
1989	1117
1990	1367
1991	100
1992	50
1993	0
1994	0
1995	0
1996	20
1997	100300
1998	630
1999	2342
2000	982
2001	23
2002	0
2003	277
2004	56
2005	747
2006	4795
2007	3809
2008	416