Year Annual Number 1970 0 1971 0 1972 0 1974 31500 1975 107 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 300 1985 0 1986 34720 1987 0 1988 170 1989 0 1990 0 1991 15440 1992 0 1993 0 1994 0 1995 112900 1996 0 1997 25900 1998 214400 1999 238 2000 0 2001 0 2002 317800 2003 0 2004 0 2005 0 2006 0 2007 0 2008 162800