| Year | Value | | 2021 | 54,741 | | 2020 | 42,693 | | 2019 | 91,864 | | 2018 | 90,017 | | 2017 | 47,741 | | 2016 | 27,422 | | 2015 | 35,374 | | 2014 | 31,106.181 | | 2013 | 27,625.772 | | 2012 | 28,130.472072972 | | 2011 | 26,332.300586101 | | 2010 | 21,825 | | 2009 | 21,088 | | 2008 | 5,460 | | 2007 | 5,457 | | 2006 | 5,068 | | 2005 | 6,062 | | 2004 | 6,441 | | 2003 | 6,082 | | 2002 | 4,401 | | 2001 | 4,360 | | 2000 | 5,973 | | 1999 | 5,000 | | 1998 | 6,100 | | 1997 | 6,000 | | 1996 | 6,100 | | 1995 | 5,600 | | 1994 | 5,400 | | 1993 | 5,700 | | 1992 | 7,500 | | 1991 | 9,400 | | 1990 | 7,500 | | 1989 | 8,000 | | 1988 | 12,100 | | 1987 | 12,300 | | 1986 | 11,200 | | 1985 | 13,800 | | 1984 | 10,400 | | 1983 | 11,800 | | 1982 | 13,400 | | 1981 | 18,700 | | 1980 | 17,500 | | 1979 | 13,000 | | 1978 | 8,900 | | 1977 | 4,100 | | 1976 | 14,900 | | 1975 | 13,700 | | 1974 | 9,000 | | 1973 | 11,500 | | 1972 | 9,600 | | 1971 | 10,000 | | 1970 | 10,500 |
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