Year | Value | 2021 | 17,557 | 2020 | 14,170 | 2019 | 36,763 | 2018 | 41,446 | 2017 | 39,856 | 2016 | 38,631 | 2015 | 35,540 | 2014 | 60,419 | 2013 | 48,804 | 2012 | 37,233 | 2011 | 32,179.916897507 | 2010 | 31,098 | 2009 | 24,225 | 2008 | 24,385 | 2007 | 21,734 | 2006 | 21,715 | 2005 | 21,268 | 2004 | 20,554 | 2003 | 18,738 | 2002 | 18,538 | 2001 | 19,385 | 2000 | 19,907 | 1999 | 20,100 | 1998 | 19,700 | 1997 | 17,200 | 1996 | 13,800 | 1995 | 14,900 | 1994 | 14,400 | 1993 | 13,300 | 1992 | 12,500 | 1991 | 12,300 | 1990 | 12,900 | 1989 | 13,100 | 1988 | 12,500 | 1987 | 13,000 | 1986 | 11,200 | 1985 | 13,800 | 1984 | 13,800 | 1983 | 13,700 | 1982 | 13,800 | 1981 | 13,500 | 1980 | 12,300 | 1979 | 12,500 | 1978 | 11,300 | 1977 | 10,800 | 1976 | 11,300 | 1975 | 11,200 | 1974 | 9,500 | 1973 | 8,600 | 1972 | 6,900 | 1971 | 5,700 | 1970 | 6,600 |
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