Year | Value | 2021 | 79.923922993616 | 2020 | 80.080865263857 | 2019 | 80.984292136163 | 2018 | 80.76904160149 | 2017 | 80.682280732872 | 2016 | 80.642481852801 | 2015 | 80.484032383544 | 2014 | 80.598915280648 | 2013 | 80.343408999554 | 2012 | 80.152023738925 | 2011 | 80.032392159351 | 2010 | 79.760762627827 | 2009 | 79.575833160087 | 2008 | 79.279280681178 | 2007 | 79.119222621336 | 2006 | 78.889104256035 | 2005 | 78.571112780672 | 2004 | 78.456835561723 | 2003 | 78.029891171815 | 2002 | 77.912107841233 | 2001 | 77.75196863211 | 2000 | 77.450208896339 | 1999 | 77.139607635907 | 1998 | 76.996236635532 | 1997 | 76.800904626952 | 1996 | 76.476729118475 | 1995 | 76.117488832927 | 1994 | 76.057090468105 | 1993 | 75.777536226017 | 1992 | 75.707179343814 | 1991 | 75.446482517049 | 1990 | 75.261105511491 | 1989 | 75.118571393016 | 1988 | 74.892891407694 | 1987 | 74.781994778535 | 1986 | 74.507345456019 | 1985 | 74.262739748353 | 1984 | 74.152533808969 | 1983 | 73.867117209599 | 1982 | 73.768589666662 | 1981 | 73.445729309313 | 1980 | 73.073557808143 | 1979 | 73.042151145013 | 1978 | 72.704471987192 | 1977 | 72.555973946533 | 1976 | 72.157669364481 | 1975 | 71.891358554665 | 1974 | 71.580071626329 | 1973 | 71.192072183922 | 1972 | 71.007542522687 | 1971 | 70.773030518064 | 1970 | 70.461010373678 | 1969 | 70.166001430831 | 1968 | 70.033617796019 | 1967 | 70.169510564129 | 1966 | 69.890685097263 | 1965 | 69.620231347524 | 1964 | 69.496624733051 | 1963 | 69.013925259195 | 1962 | 68.777240941807 | 1961 | 68.815156434899 | 1960 | 68.414642147497 |
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