Year | Value | 2022 | 49.897469629755 | 2021 | 49.885496274284 | 2020 | 49.873033568576 | 2019 | 49.862089800602 | 2018 | 49.853767008569 | 2017 | 49.846684363066 | 2016 | 49.839563192465 | 2015 | 49.832943756752 | 2014 | 49.82573074899 | 2013 | 49.815404590278 | 2012 | 49.805540654456 | 2011 | 49.797795415622 | 2010 | 49.790965030549 | 2009 | 49.785240316233 | 2008 | 49.779631550758 | 2007 | 49.772626873291 | 2006 | 49.765747805757 | 2005 | 49.761206408775 | 2004 | 49.755971993297 | 2003 | 49.752486838698 | 2002 | 49.752520547662 | 2001 | 49.754312848283 | 2000 | 49.756367476913 | 1999 | 49.755941893924 | 1998 | 49.751123439391 | 1997 | 49.741276466866 | 1996 | 49.725586686013 | 1995 | 49.706146120977 | 1994 | 49.68797169957 | 1993 | 49.671600064516 | 1992 | 49.655970661335 | 1991 | 49.640309801507 | 1990 | 49.623900571264 | 1989 | 49.606639106007 | 1988 | 49.588494973895 | 1987 | 49.569726461028 | 1986 | 49.552360369264 | 1985 | 49.535791618865 | 1984 | 49.51846811643 | 1983 | 49.500404924473 | 1982 | 49.481426968036 | 1981 | 49.461775480569 | 1980 | 49.441594821372 | 1979 | 49.421147870256 | 1978 | 49.400402965601 | 1977 | 49.380059552354 | 1976 | 49.361166040263 | 1975 | 49.343784156659 | 1974 | 49.32749683493 | 1973 | 49.312367236427 | 1972 | 49.297895786325 | 1971 | 49.281429588696 | 1970 | 49.26388052805 | 1969 | 49.245495265044 | 1968 | 49.224387483797 | 1967 | 49.203356521463 | 1966 | 49.18208003051 | 1965 | 49.158794302108 | 1964 | 49.134675091971 | 1963 | 49.108848389899 | 1962 | 49.08030275212 | 1961 | 49.049765099144 | 1960 | 49.016644255404 |
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