Year | Value | 2023 | 72.76 | 2022 | 71.73 | 2021 | 69.81 | 2020 | 71.537 | 2019 | 72.653 | 2018 | 72.365 | 2017 | 72.069 | 2016 | 71.716 | 2015 | 71.818 | 2014 | 71.462 | 2013 | 71.246 | 2012 | 70.945 | 2011 | 70.654 | 2010 | 70.392 | 2009 | 70.076 | 2008 | 69.733 | 2007 | 69.368 | 2006 | 68.953 | 2005 | 68.485 | 2004 | 68.019 | 2003 | 67.558 | 2002 | 67.085 | 2001 | 66.699 | 2000 | 66.347 | 1999 | 66.014 | 1998 | 65.683 | 1997 | 65.37 | 1996 | 64.992 | 1995 | 64.6 | 1994 | 64.21 | 1993 | 63.831 | 1992 | 63.557 | 1991 | 63.348 | 1990 | 63.133 | 1989 | 62.907 | 1988 | 62.674 | 1987 | 62.364 | 1986 | 61.989 | 1985 | 61.601 | 1984 | 61.194 | 1983 | 60.781 | 1982 | 60.382 | 1981 | 59.969 | 1980 | 59.543 | 1979 | 59.103 | 1978 | 58.674 | 1977 | 58.205 | 1976 | 57.73 | 1975 | 57.255 |
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