| Year | Value | | 2022 | 920 | | 2021 | 910 | | 2020 | 931 | | 2019 | 936 | | 2018 | 924 | | 2017 | 918 | | 2016 | 903 | | 2015 | 889 | | 2014 | 911 | | 2013 | 944 | | 2012 | 942 | | 2011 | 932 | | 2010 | 915 | | 2009 | 884 | | 2008 | 858 | | 2007 | 841 | | 2006 | 842 | | 2005 | 849 | | 2004 | 850 | | 2003 | 844 | | 2002 | 833 | | 2001 | 815 | | 2000 | 795 | | 1999 | 775 | | 1998 | 750 | | 1997 | 722 | | 1996 | 700 | | 1995 | 684 | | 1994 | 677 | | 1993 | 676 | | 1992 | 672 | | 1991 | 659 | | 1990 | 632 | | 1989 | 595 | | 1988 | 562 | | 1987 | 540 | | 1986 | 531 | | 1985 | 529 | | 1984 | 521 | | 1983 | 505 | | 1982 | 483 | | 1981 | 467 | | 1980 | 459 | | 1979 | 451 | | 1978 | 446 | | 1977 | 443 | | 1976 | 439 | | 1975 | 433 | | 1974 | 422 | | 1973 | 411 | | 1972 | 400 | | 1971 | 389 | | 1970 | 380 | | 1969 | 372 | | 1968 | 364 | | 1967 | 358 | | 1966 | 348 | | 1965 | 336 | | 1964 | 326 | | 1963 | 319 | | 1962 | 312 | | 1961 | 308 | | 1960 | 305 |
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