Year | Value | 2021 | 16.941925079351 | 2020 | 16.961123984818 | 2019 | 16.922960155552 | 2018 | 16.957851821139 | 2017 | 16.940398487648 | 2016 | 16.894195284891 | 2015 | 16.814795462881 | 2014 | 16.754025341515 | 2013 | 16.766621327127 | 2012 | 16.717367889533 | 2011 | 16.692766339072 | 2010 | 16.612271859403 | 2009 | 16.681528873395 | 2008 | 16.570903182683 | 2007 | 16.553648910308 | 2006 | 16.544958225485 | 2005 | 16.524609706966 | 2004 | 16.521193556869 | 2003 | 16.546439696983 | 2002 | 16.518258718109 | 2001 | 16.507119096782 | 2000 | 16.455146346886 | 1999 | 16.539839811826 | 1998 | 16.481940647725 | 1997 | 16.448112610276 | 1996 | 16.395897281457 | 1995 | 16.426267931651 | 1994 | 16.334368020038 | 1993 | 16.274294448302 | 1992 | 16.230640166922 | 1991 | 15.347398587738 | 1990 | 15.240897498549 | 1989 | 15.278131219999 | 1988 | 15.184445092456 | 1987 | 15.184537680751 | 1986 | 15.08184844377 | 1985 | 15.116635188855 | 1984 | 15.018798460321 | 1983 | 14.872922515424 | 1982 | 14.971348281872 | 1981 | 14.816402211248 | 1980 | 14.80619104501 | 1979 | 14.874022993443 | 1978 | 14.838067872255 | 1977 | 14.73745525846 | 1976 | 14.728020070313 | 1975 | 14.706327955507 | 1974 | 14.64392816769 | 1973 | 14.648972639898 | 1972 | 14.535705820557 | 1971 | 14.449422842184 | 1970 | 14.492343884313 | 1969 | 14.392371143658 | 1968 | 14.456256700972 | 1967 | 14.433462475208 | 1966 | 14.353440193273 | 1965 | 14.298063892386 | 1964 | 14.198686358787 | 1963 | 14.143618683781 | 1962 | 14.036260966695 | 1961 | 13.990937051637 |
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