Year | Value | 2022 | 52.403819462914 | 2021 | 52.454181586707 | 2020 | 52.543743267328 | 2019 | 52.663212337706 | 2018 | 52.747533945365 | 2017 | 52.76667802048 | 2016 | 52.69676367094 | 2015 | 52.526132841204 | 2014 | 52.310798931343 | 2013 | 52.139313242192 | 2012 | 52.03340214218 | 2011 | 51.963021220552 | 2010 | 51.929642718859 | 2009 | 51.859254163662 | 2008 | 51.635684198276 | 2007 | 51.28316445369 | 2006 | 50.875516341343 | 2005 | 50.537150273498 | 2004 | 50.375124574379 | 2003 | 50.29973672824 | 2002 | 50.234643951832 | 2001 | 50.183430785373 | 2000 | 50.134364615313 | 1999 | 50.091974523342 | 1998 | 50.057510703332 | 1997 | 50.031014461368 | 1996 | 50.017718851008 | 1995 | 50.013285605047 | 1994 | 50.009521688122 | 1993 | 50.006268218427 | 1992 | 50.00868970067 | 1991 | 50.013005646276 | 1990 | 50.004374458019 | 1989 | 49.983704946526 | 1988 | 49.96591293515 | 1987 | 49.951827733947 | 1986 | 49.940352856371 | 1985 | 49.92083720424 | 1984 | 49.887290190788 | 1983 | 49.853194935082 | 1982 | 49.819827648821 | 1981 | 49.778804393321 | 1980 | 49.720428532836 | 1979 | 49.64160447103 | 1978 | 49.557369641383 | 1977 | 49.474503026521 | 1976 | 49.384410174652 | 1975 | 49.28724605115 | 1974 | 49.198055203434 | 1973 | 49.10663652441 | 1972 | 49.001371605132 | 1971 | 48.901769302977 | 1970 | 48.819895704747 | 1969 | 48.756498931415 | 1968 | 48.696213210737 | 1967 | 48.631315124861 | 1966 | 48.586849100201 | 1965 | 48.566352311613 | 1964 | 48.540596604672 | 1963 | 48.506383728609 | 1962 | 48.464488055985 | 1961 | 48.417952987909 | 1960 | 48.373025282201 |
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