Year | Value | 2021 | 72.41 | 2020 | 72.2 | 2019 | 74.7 | 2018 | 74.6 | 2017 | 74.1 | 2016 | 73.4 | 2015 | 73.5 | 2014 | 73.5 | 2013 | 73.4 | 2012 | 73 | 2011 | 73.1 | 2010 | 72.9 | 2009 | 72.3 | 2008 | 72.4 | 2007 | 71.8 | 2006 | 71.7 | 2005 | 71.6 | 2004 | 71.5 | 2003 | 70.9 | 2002 | 70.6 | 2001 | 70.9 | 2000 | 70.8 | 1999 | 70.4 | 1998 | 70.2 | 1997 | 70.3 | 1996 | 70.3 | 1995 | 69.8 | 1994 | 69.4 | 1993 | 69.457 | 1992 | 68.847 | 1991 | 69.522 | 1990 | 68.826 | 1989 | 69.09 | 1988 | 68.937 | 1987 | 68.521 | 1986 | 68.503 | 1985 | 67.885 | 1984 | 67.912 | 1983 | 67.47 | 1982 | 68.098 | 1981 | 67.77 | 1980 | 67.232 | 1979 | 67.759 | 1978 | 67.605 | 1977 | 66.561 | 1976 | 65.968 | 1975 | 65.319 | 1974 | 64.892 | 1973 | 64.261 | 1972 | 63.895 | 1971 | 62.942 | 1970 | 62.155 | 1969 | 61.509 | 1968 | 61.495 | 1967 | 60.782 | 1966 | 60.734 | 1965 | 58.739 | 1964 | 57.783 | 1963 | 55.653 | 1962 | 56.377 | 1961 | 56.693 | 1960 | 55.125 |
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