Year | Value | 2022 | 49.480968621951 | 2021 | 49.461486770777 | 2020 | 49.445682861436 | 2019 | 49.428680174412 | 2018 | 49.403386036472 | 2017 | 49.383032230155 | 2016 | 49.37434587864 | 2015 | 49.365689286693 | 2014 | 49.364890032553 | 2013 | 49.374444161396 | 2012 | 49.384467477909 | 2011 | 49.394754433751 | 2010 | 49.405826378703 | 2009 | 49.417303808234 | 2008 | 49.431128735715 | 2007 | 49.446367115167 | 2006 | 49.460983366428 | 2005 | 49.477481266889 | 2004 | 49.497279896993 | 2003 | 49.518334399188 | 2002 | 49.54005851179 | 2001 | 49.562761835545 | 2000 | 49.585650099041 | 1999 | 49.608982877413 | 1998 | 49.63307012731 | 1997 | 49.658193989356 | 1996 | 49.684459062619 | 1995 | 49.712497513714 | 1994 | 49.739696168711 | 1993 | 49.768385434073 | 1992 | 49.801101874209 | 1991 | 49.833651785702 | 1990 | 49.867690916591 | 1989 | 49.903925946147 | 1988 | 49.939889747819 | 1987 | 49.975657885406 | 1986 | 49.988478422641 | 1985 | 50.000960413043 | 1984 | 50.037875198093 | 1983 | 50.074633273263 | 1982 | 50.11416801691 | 1981 | 50.155528772115 | 1980 | 50.1959057193 | 1979 | 50.2352604888 | 1978 | 50.273275420093 | 1977 | 50.308785793122 | 1976 | 50.338685000652 | 1975 | 50.364877183411 | 1974 | 50.38951847857 | 1973 | 50.410650904804 | 1972 | 50.427760612597 | 1971 | 50.442000764216 | 1970 | 50.449989311192 | 1969 | 50.448825071573 | 1968 | 50.436731419002 | 1967 | 50.412059395598 | 1966 | 50.380673781354 | 1965 | 50.346448541633 | 1964 | 50.307584632436 | 1963 | 50.251672426712 | 1962 | 50.186116488621 | 1961 | 50.133512365168 | 1960 | 50.090167559201 |
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