| Year | Value | | 2004 | 12,277,222 | | 2003 | 12,805,757 | | 2002 | 13,699,204 | | 2001 | 14,556,181 | | 2000 | 15,182,305 | | 1999 | 15,009,600 | | 1998 | 14,291,500 | | 1997 | 13,759,000 | | 1996 | 12,727,300 | | 1995 | 11,695,500 | | 1994 | 11,133,100 | | 1993 | 10,383,600 | | 1992 | 9,661,200 | | 1991 | 8,857,300 | | 1990 | 8,928,500 | | 1989 | 8,300,000 | | 1988 | 8,261,000 | | 1987 | 8,146,000 | | 1986 | 7,485,200 | | 1985 | 6,799,700 | | 1984 | 6,113,900 | | 1983 | 5,610,800 | | 1982 | 5,210,400 | | 1981 | 4,979,400 | | 1980 | 4,804,400 | | 1979 | 4,866,900 | | 1978 | 4,487,400 | | 1977 | 4,192,500 | | 1976 | 3,853,500 | | 1975 | 3,530,400 | | 1974 | 3,367,500 | | 1973 | 3,342,600 | | 1972 | 3,101,600 | | 1971 | 2,791,600 | | 1970 | 2,412,300 |
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