Year	Annual Number
1970	0
1971	112
1972	0
1973	100
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	308
1981	0
1982	70
1983	734
1984	155
1985	798
1986	435
1987	123
1988	157
1989	959
1990	102
1991	297
1992	31
1993	206
1994	30
1995	16
1996	789
1997	3692
1998	368
1999	10
2000	23
2001	53
2002	0
2003	0
2004	70
2005	116
2006	401
2007	96
2008	254