| Year | Value | | 2021 | 11,917,901.427 | | 2020 | 8,026,937.252 | | 2019 | 18,690,732.685887 | | 2018 | 17,823,482.468118 | | 2017 | 15,919,522.08 | | 2016 | 13,753,911 | | 2015 | 12,867,667 | | 2014 | 14,719,339.159068 | | 2013 | 14,815,345 | | 2012 | 13,737,452.860049 | | 2011 | 14,168,273.539127 | | 2010 | 11,761,536.134862 | | 2001 | 4,640,077 | | 2000 | 4,776,260 | | 1999 | 4,601,000 | | 1998 | 4,508,400 | | 1997 | 4,462,000 | | 1996 | 4,464,600 | | 1995 | 4,168,400 | | 1994 | 4,490,400 | | 1993 | 4,392,300 | | 1992 | 4,436,300 | | 1991 | 4,109,300 | | 1990 | 4,670,900 | | 1989 | 4,305,700 | | 1988 | 4,291,800 | | 1987 | 4,155,300 | | 1986 | 4,160,000 | | 1985 | 3,859,300 | | 1984 | 4,251,100 | | 1983 | 4,210,500 | | 1982 | 4,133,500 | | 1981 | 4,082,100 | | 1980 | 3,876,500 | | 1979 | 3,600,900 | | 1978 | 3,283,900 | | 1977 | 3,188,700 | | 1976 | 3,055,300 | | 1975 | 2,412,200 | | 1974 | 2,194,700 | | 1973 | 1,923,200 | | 1972 | 1,890,900 | | 1971 | 1,958,800 | | 1970 | 1,771,600 |
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