| Year | Value | | 2024 | 561 | | 2023 | 559 | | 2022 | 557 | | 2021 | 556 | | 2020 | 559 | | 2019 | 567 | | 2018 | 581 | | 2017 | 593 | | 2016 | 604 | | 2015 | 615 | | 2014 | 638 | | 2013 | 677 | | 2012 | 705 | | 2011 | 712 | | 2010 | 721 | | 2009 | 737 | | 2008 | 758 | | 2007 | 784 | | 2006 | 814 | | 2005 | 839 | | 2004 | 853 | | 2003 | 858 | | 2002 | 850 | | 2001 | 825 | | 2000 | 787 | | 1999 | 751 | | 1998 | 723 | | 1997 | 699 | | 1996 | 679 | | 1995 | 654 | | 1994 | 623 | | 1993 | 594 | | 1992 | 571 | | 1991 | 551 | | 1990 | 530 | | 1989 | 497 | | 1988 | 454 | | 1987 | 414 | | 1986 | 379 | | 1985 | 355 | | 1984 | 334 | | 1983 | 314 | | 1982 | 301 | | 1981 | 288 | | 1980 | 273 | | 1979 | 270 | | 1978 | 269 | | 1977 | 267 | | 1976 | 264 | | 1975 | 259 |
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