Year | Value | 2021 | 73.4 | 2020 | 74.7 | 2019 | 75.4 | 2018 | 74.9 | 2017 | 74.9 | 2016 | 74.9 | 2015 | 74.3 | 2014 | 74.6 | 2013 | 74.2 | 2012 | 73.9 | 2011 | 73.8 | 2010 | 73.5 | 2009 | 72.9 | 2008 | 72.4 | 2007 | 72.33 | 2006 | 72.51 | 2005 | 71.83 | 2004 | 72.13 | 2003 | 71.17 | 2002 | 71.21 | 2001 | 71.03 | 2000 | 69.12 | 1999 | 68.92 | 1998 | 68.6 | 1997 | 68.3 | 1996 | 68.18 | 1995 | 67.86 | 1994 | 67.54 | 1993 | 67.22 | 1992 | 66.9 | 1991 | 68.6 | 1990 | 68.59 | 1989 | 68.23 | 1988 | 67.82 | 1987 | 67.88 | 1986 | 67.78 | 1985 | 67.13 | 1984 | 66.36 | 1983 | 66.47 | 1982 | 66.79 | 1981 | 66.72 | 1980 | 66.39 | 1979 | 66.92 | 1978 | 67.09 | 1977 | 67.52 | 1976 | 67.27 | 1975 | 66.68 | 1974 | 66.39 | 1973 | 66.128 | 1972 | 65.673 | 1971 | 65.487 | 1970 | 65.118 | 1969 | 65.072 | 1968 | 65.023 | 1967 | 64.997 | 1966 | 65.139 | 1965 | 64.835 | 1964 | 64.385 | 1963 | 64.048 | 1962 | 63.615 | 1961 | 63.434 | 1960 | 62.777 |
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