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	25
1988	0
1989	22
1990	0
1991	146
1992	101
1993	103
1994	22
1995	0
1996	32
1997	436
1998	11
1999	0
2000	0
2001	0
2002	10
2003	0
2004	95
2005	182
2006	12
2007	174
2008	0