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	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	153
1992	142
1993	35
1994	431
1995	97
1996	61
1997	141
1998	0
1999	26
2000	19
2001	289
2002	98
2003	57
2004	105
2005	69
2006	332
2007	0
2008	88