| Year | Value | | 2021 | 4,874.098 | | 2020 | 3,787.864 | | 2019 | 7,532 | | 2018 | 8,271 | | 2017 | 18,757 | | 2016 | 11,513 | | 2015 | 12,476 | | 2014 | 11,580 | | 2013 | 11,448 | | 2012 | 4,781 | | 2011 | 2,295 | | 2010 | 1,945 | | 2001 | 5,200 | | 1994 | 3,900 | | 1993 | 2,600 | | 1992 | 3,000 | | 1991 | 3,500 | | 1990 | 5,100 | | 1989 | 4,800 | | 1988 | 4,500 | | 1987 | 5,200 | | 1986 | 5,000 | | 1985 | 3,900 | | 1984 | 7,600 | | 1983 | 7,400 | | 1982 | 9,200 | | 1981 | 12,200 | | 1980 | 11,800 | | 1979 | 13,600 | | 1978 | 14,100 | | 1977 | 15,800 | | 1976 | 18,600 | | 1975 | 19,200 | | 1974 | 12,000 | | 1973 | 8,900 | | 1972 | 8,100 | | 1971 | 7,900 | | 1970 | 8,300 |
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