| Year | Value | | 2024 | 596 | | 2023 | 593 | | 2022 | 584 | | 2021 | 571 | | 2020 | 553 | | 2019 | 541 | | 2018 | 545 | | 2017 | 563 | | 2016 | 594 | | 2015 | 632 | | 2014 | 677 | | 2013 | 729 | | 2012 | 762 | | 2011 | 775 | | 2010 | 785 | | 2009 | 789 | | 2008 | 784 | | 2007 | 772 | | 2006 | 752 | | 2005 | 728 | | 2004 | 711 | | 2003 | 714 | | 2002 | 729 | | 2001 | 742 | | 2000 | 743 | | 1999 | 736 | | 1998 | 728 | | 1997 | 718 | | 1996 | 705 | | 1995 | 701 | | 1994 | 714 | | 1993 | 739 | | 1992 | 767 | | 1991 | 789 | | 1990 | 803 | | 1989 | 812 | | 1988 | 823 | | 1987 | 834 | | 1986 | 846 | | 1985 | 854 | | 1984 | 862 | | 1983 | 869 | | 1982 | 875 | | 1981 | 874 | | 1980 | 865 | | 1979 | 850 | | 1978 | 834 | | 1977 | 819 | | 1976 | 812 | | 1975 | 815 |
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