Year | Value | 2022 | 49.742187380423 | 2021 | 49.746532964434 | 2020 | 49.768734421367 | 2019 | 49.782347926277 | 2018 | 49.769594865729 | 2017 | 49.747950840458 | 2016 | 49.718799205664 | 2015 | 49.675672481574 | 2014 | 49.636237805874 | 2013 | 49.60903198356 | 2012 | 49.578656344902 | 2011 | 49.546422997439 | 2010 | 49.524725319123 | 2009 | 49.504451682163 | 2008 | 49.467411343609 | 2007 | 49.422195751348 | 2006 | 49.379460274281 | 2005 | 49.347651954863 | 2004 | 49.33218549128 | 2003 | 49.326458164946 | 2002 | 49.323295626449 | 2001 | 49.321110813153 | 2000 | 49.313125315288 | 1999 | 49.300669935451 | 1998 | 49.290511620614 | 1997 | 49.281515734177 | 1996 | 49.272939041672 | 1995 | 49.264497074725 | 1994 | 49.25476060946 | 1993 | 49.242104850424 | 1992 | 49.227585506482 | 1991 | 49.209568205393 | 1990 | 49.192838105993 | 1989 | 49.175621958546 | 1988 | 49.155166731084 | 1987 | 49.136169557796 | 1986 | 49.11667198141 | 1985 | 49.098141654466 | 1984 | 49.083336539935 | 1983 | 49.070274836709 | 1982 | 49.057825138001 | 1981 | 49.046980016632 | 1980 | 49.03306512401 | 1979 | 49.020294030291 | 1978 | 49.013358470757 | 1977 | 49.007544537627 | 1976 | 49.000205542511 | 1975 | 48.992137650616 | 1974 | 48.982102308805 | 1973 | 48.97059690327 | 1972 | 48.957323781825 | 1971 | 48.937972725146 | 1970 | 48.913813415791 | 1969 | 48.897081250968 | 1968 | 48.891857899657 | 1967 | 48.897973390329 | 1966 | 48.913438338785 | 1965 | 48.924458638562 | 1964 | 48.923046853025 | 1963 | 48.914737049566 | 1962 | 48.906422184057 | 1961 | 48.898452340329 | 1960 | 48.889412696194 |
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