Year	Annual Number
1970	0
1971	0
1972	50
1973	427
1974	28700
1975	0
1976	168
1977	13
1978	17
1979	0
1980	655
1981	0
1982	0
1983	245
1984	1200
1985	34
1986	30
1987	2280
1988	2440
1989	180
1990	231
1991	265
1992	17
1993	194
1994	116
1995	741
1996	55
1997	79
1998	1050
1999	196
2000	43
2001	9
2002	10
2003	252
2004	761
2005	55
2006	0
2007	1230
2008	28