| Year | Value | | 2021 | 7,071.541 | | 2020 | 777.3744 | | 2019 | 1,298 | | 2018 | 1,241 | | 2017 | 9,020 | | 2016 | 8,094 | | 2015 | 11,130 | | 2014 | 8,050 | | 2013 | 7,997 | | 2012 | 8,288 | | 2011 | 11,497 | | 2010 | 9,730 | | 2008 | 4,361 | | 2007 | 6,396 | | 2006 | 6,013 | | 2005 | 5,965 | | 2004 | 5,825 | | 2003 | 5,214 | | 2002 | 4,875 | | 2001 | 4,886 | | 2000 | 6,118 | | 1999 | 5,400 | | 1998 | 1,200 | | 1997 | 1,200 | | 1994 | 4,300 | | 1993 | 4,200 | | 1992 | 2,700 | | 1991 | 2,800 | | 1990 | 6,500 | | 1989 | 2,900 | | 1988 | 5,600 | | 1987 | 5,400 | | 1986 | 4,900 | | 1985 | 4,700 | | 1984 | 5,700 | | 1983 | 6,000 | | 1982 | 6,500 | | 1981 | 5,400 | | 1980 | 6,800 | | 1979 | 9,200 | | 1978 | 10,500 | | 1977 | 9,300 | | 1976 | 12,800 | | 1975 | 11,200 | | 1974 | 10,000 | | 1973 | 10,000 | | 1972 | 10,800 | | 1971 | 10,600 | | 1970 | 9,300 |
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