Year Annual Number 1970 0 1971 0 1972 0 1974 0 1975 0 1976 507 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 498 1988 0 1989 0 1990 0 1991 500 1992 0 1993 0 1994 0 1995 233 1996 2156 1997 1465 1998 14890 1999 75 2000 89 2001 11930 2002 541900 2003 21190 2004 46930 2005 4973 2006 3137 2007 591 2008 0