Year | Value | 2021 | 77.24 | 2020 | 77.66 | 2019 | 77.56 | 2018 | 77.72 | 2017 | 77.89 | 2016 | 77.76 | 2015 | 77.79 | 2014 | 77.58 | 2013 | 77.5 | 2012 | 77.5 | 2011 | 76.97 | 2010 | 76.65 | 2009 | 76.56 | 2008 | 76.11 | 2007 | 76.11 | 2006 | 75.91 | 2005 | 75.91 | 2004 | 75.8 | 2003 | 75.6 | 2002 | 75.5 | 2001 | 75.3 | 2000 | 75.3 | 1999 | 74.7 | 1998 | 74.5 | 1997 | 74.4 | 1996 | 74.4 | 1995 | 74.28 | 1994 | 74 | 1993 | 74 | 1992 | 73.9 | 1991 | 73.9 | 1990 | 73.4 | 1989 | 72.835 | 1988 | 72.174 | 1987 | 71.668 | 1986 | 71.318 | 1985 | 71.013 | 1984 | 70.834 | 1983 | 70.703 | 1982 | 70.405 | 1981 | 70.078 | 1980 | 69.66 | 1979 | 69.383 | 1978 | 68.671 | 1977 | 67.769 | 1976 | 67.034 | 1975 | 66.165 | 1974 | 65.371 | 1973 | 64.177 | 1972 | 63.99 | 1971 | 64.119 | 1970 | 64.114 | 1969 | 62.732 | 1968 | 61.51 | 1967 | 61.343 | 1966 | 62.208 | 1965 | 62.535 | 1964 | 61.849 | 1963 | 60.948 | 1962 | 60.083 | 1961 | 59.211 | 1960 | 58.237 |
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