Year | Value | 2021 | 78.715486915502 | 2020 | 78.900039536709 | 2019 | 80.223651188445 | 2018 | 80.011561554613 | 2017 | 79.933335373273 | 2016 | 79.906872055576 | 2015 | 79.794139933109 | 2014 | 79.919009408206 | 2013 | 79.670802793493 | 2012 | 79.474257193125 | 2011 | 79.319678109639 | 2010 | 79.092733360011 | 2009 | 78.920022767116 | 2008 | 78.656474067831 | 2007 | 78.5050533365 | 2006 | 78.29782141009 | 2005 | 78.011833058647 | 2004 | 77.898546548333 | 2003 | 77.505306781989 | 2002 | 77.378698655601 | 2001 | 77.203441259557 | 2000 | 76.916428581544 | 1999 | 76.574533054873 | 1998 | 76.458663883288 | 1997 | 76.25545147782 | 1996 | 75.919821748004 | 1995 | 75.546340004912 | 1994 | 75.45626602556 | 1993 | 75.168226846154 | 1992 | 75.066151332061 | 1991 | 74.795371464565 | 1990 | 74.6030747872 | 1989 | 74.4479845513 | 1988 | 74.207640738708 | 1987 | 74.067037944666 | 1986 | 73.773516559606 | 1985 | 73.452144336929 | 1984 | 73.363650214539 | 1983 | 73.054101310327 | 1982 | 72.915549075387 | 1981 | 72.561832644178 | 1980 | 72.175393957499 | 1979 | 72.1059965997 | 1978 | 71.749593663475 | 1977 | 71.576135701152 | 1976 | 71.166054545631 | 1975 | 70.892596610074 | 1974 | 70.592267688803 | 1973 | 70.200844461822 | 1972 | 70.014419278868 | 1971 | 69.756791126312 | 1970 | 69.460593903071 | 1969 | 69.180579003164 | 1968 | 69.027738592293 | 1967 | 69.140048772255 | 1966 | 68.821857046304 | 1965 | 68.564902764983 | 1964 | 68.430435546918 | 1963 | 67.965513419982 | 1962 | 67.747226923326 | 1961 | 67.73093492757 | 1960 | 67.306220088469 |
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