Year | Value | 2021 | 79.797714011758 | 2020 | 80.004458054754 | 2019 | 80.899073566667 | 2018 | 80.671121203144 | 2017 | 80.583686584033 | 2016 | 80.539509702776 | 2015 | 80.38202541606 | 2014 | 80.516012846121 | 2013 | 80.260215477018 | 2012 | 80.083872477206 | 2011 | 79.950385255858 | 2010 | 79.685190812689 | 2009 | 79.475611009377 | 2008 | 79.151087696378 | 2007 | 79.005590206396 | 2006 | 78.758586913272 | 2005 | 78.426553145263 | 2004 | 78.339361422702 | 2003 | 77.909451473475 | 2002 | 77.795989021359 | 2001 | 77.644033738638 | 2000 | 77.34938362876 | 1999 | 77.097304639526 | 1998 | 76.990976029348 | 1997 | 76.774990372936 | 1996 | 76.437285126064 | 1995 | 76.059677462966 | 1994 | 76.038724757021 | 1993 | 75.722376269497 | 1992 | 75.710016509005 | 1991 | 75.594095779648 | 1990 | 75.467365043781 | 1989 | 75.35244758936 | 1988 | 75.112792319294 | 1987 | 75.01048406202 | 1986 | 74.723218942125 | 1985 | 74.402802798807 | 1984 | 74.280994018787 | 1983 | 74.015421650113 | 1982 | 73.919144430715 | 1981 | 73.58755232664 | 1980 | 73.24657875075 | 1979 | 73.212984151651 | 1978 | 72.892394532137 | 1977 | 72.749849658793 | 1976 | 72.365759945805 | 1975 | 72.094990545704 | 1974 | 71.787061589892 | 1973 | 71.42494180775 | 1972 | 71.254468981381 | 1971 | 71.051181432677 | 1970 | 70.747421605001 | 1969 | 70.482248426093 | 1968 | 70.35578769808 | 1967 | 70.523627073523 | 1966 | 70.218802510515 | 1965 | 69.995426835432 | 1964 | 69.925686162564 | 1963 | 69.441361105285 | 1962 | 69.238700680509 | 1961 | 69.274126973279 | 1960 | 68.865666017357 |
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