| Year | Value | | 2004 | 75,416 | | 2003 | 60,819 | | 2002 | 58,480 | | 2001 | 56,777 | | 2000 | 51,615 | | 1999 | 50,300 | | 1998 | 48,800 | | 1997 | 49,000 | | 1996 | 56,000 | | 1995 | 53,300 | | 1994 | 53,300 | | 1993 | 35,300 | | 1992 | 35,300 | | 1991 | 34,600 | | 1990 | 34,600 | | 1989 | 33,900 | | 1988 | 33,200 | | 1987 | 37,300 | | 1986 | 30,200 | | 1985 | 8,000 | | 1984 | 7,800 |
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