| Year | Value | | 2024 | 590 | | 2023 | 577 | | 2022 | 558 | | 2021 | 536 | | 2020 | 513 | | 2019 | 499 | | 2018 | 501 | | 2017 | 517 | | 2016 | 543 | | 2015 | 570 | | 2014 | 603 | | 2013 | 652 | | 2012 | 690 | | 2011 | 708 | | 2010 | 726 | | 2009 | 745 | | 2008 | 766 | | 2007 | 777 | | 2006 | 772 | | 2005 | 750 | | 2004 | 714 | | 2003 | 678 | | 2002 | 657 | | 2001 | 648 | | 2000 | 644 | | 1999 | 641 | | 1998 | 637 | | 1997 | 629 | | 1996 | 619 | | 1995 | 618 | | 1994 | 638 | | 1993 | 663 | | 1992 | 680 | | 1991 | 685 | | 1990 | 678 | | 1989 | 681 | | 1988 | 692 | | 1987 | 695 | | 1986 | 689 | | 1985 | 692 | | 1984 | 705 | | 1983 | 719 | | 1982 | 728 | | 1981 | 725 | | 1980 | 709 | | 1979 | 694 | | 1978 | 684 | | 1977 | 680 | | 1976 | 685 | | 1975 | 697 |
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