Year Annual Number 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 3500000 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 1000000 1989 0 1990 1630000 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 8500 1998 0 1999 0 2000 0 2001 3585000 2002 0 2003 0 2004 0 2005 3000000 2006 0 2007 0 2008 0