Year | Value | 2021 | 24.841087091307 | 2020 | 24.711702558591 | 2019 | 25.154376885876 | 2018 | 24.956753606415 | 2017 | 25.143138097797 | 2016 | 24.908074649692 | 2015 | 24.846029843343 | 2014 | 25.76571735626 | 2013 | 25.897573678337 | 2012 | 25.676848675237 | 2011 | 25.056834621585 | 2010 | 24.676559335345 | 2009 | 25.003100070268 | 2008 | 24.821229281197 | 2007 | 25.151903443145 | 2006 | 25.189104286364 | 2005 | 23.680403422478 | 2004 | 24.052411854669 | 2003 | 23.391063530773 | 2002 | 23.916008762865 | 2001 | 23.357996114579 | 2000 | 24.288017195056 | 1999 | 24.457487703055 | 1998 | 25.846319183235 | 1997 | 26.321663291035 | 1996 | 25.205637994461 | 1995 | 24.536022816517 | 1994 | 24.432687140908 | 1993 | 25.176704005291 | 1992 | 27.090480717563 | 1991 | 27.144215268879 | 1990 | 27.36328690117 | 1989 | 27.702227917166 | 1988 | 28.462778489646 | 1987 | 28.665316413839 | 1986 | 28.68598354896 | 1985 | 28.892654900178 | 1984 | 28.611581862522 | 1983 | 28.516513040962 | 1982 | 28.574381019303 | 1981 | 28.549580457157 | 1980 | 28.595048154425 | 1979 | 28.227173149258 | 1978 | 28.669449840863 | 1977 | 28.607448435498 | 1976 | 28.495845905841 | 1975 | 28.392510230232 | 1974 | 29.210928781052 | 1973 | 29.243996197247 | 1972 | 29.467201256562 | 1971 | 29.479601537635 | 1970 | 29.355598726904 | 1969 | 29.60773777539 | 1968 | 30.078948456165 | 1967 | 30.211218120944 | 1966 | 30.273219526309 | 1965 | 30.335220931674 | 1964 | 30.39722233704 | 1963 | 30.070681602116 | 1962 | 29.909477948167 | 1961 | 29.657338899682 |
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