| Year | Value | | 2021 | 11,812 | | 2020 | 8,030 | | 2019 | 16,616 | | 2018 | 14,666 | | 2017 | 14,884 | | 2016 | 9,463 | | 2015 | 9,068 | | 2014 | 4,032 | | 2013 | 3,912 | | 2012 | 415 | | 2011 | 907 | | 2010 | 5,604 | | 2001 | 716 | | 2000 | 2,342 | | 1999 | 6,300 | | 1998 | 3,500 | | 1997 | 3,500 | | 1996 | 4,600 | | 1995 | 4,400 | | 1994 | 4,300 | | 1993 | 4,600 | | 1992 | 5,000 | | 1991 | 4,900 | | 1990 | 5,400 | | 1989 | 5,600 | | 1988 | 7,100 | | 1987 | 6,700 | | 1986 | 6,100 | | 1985 | 6,100 | | 1984 | 10,700 | | 1983 | 10,400 | | 1982 | 10,400 | | 1981 | 10,300 | | 1980 | 5,600 | | 1979 | 5,200 | | 1978 | 5,100 | | 1977 | 4,900 | | 1976 | 4,900 | | 1975 | 4,600 | | 1974 | 4,000 | | 1973 | 4,000 | | 1972 | 3,800 | | 1971 | 3,900 | | 1970 | 4,300 |
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