Year	Annual Number
1970	237
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	74
1979	0
1980	94
1981	0
1982	0
1983	0
1984	33
1985	93
1986	165
1987	0
1988	0
1989	0
1990	82
1991	195
1992	56
1993	64
1994	310
1995	253
1996	222
1997	0
1998	45
1999	789
2000	496
2001	339
2002	147
2003	128
2004	96
2005	192
2006	178
2007	230
2008	157