Year | Value | 2021 | 10.854916680361 | 2020 | 10.755594475801 | 2019 | 11.245335740484 | 2018 | 11.446665976366 | 2017 | 11.647962540211 | 2016 | 12.038655353952 | 2015 | 12.229202145094 | 2014 | 12.339191516664 | 2013 | 12.249809948467 | 2012 | 12.440286121922 | 2011 | 12.530882724151 | 2010 | 12.821565429039 | 2009 | 13.292383665203 | 2008 | 13.753424555069 | 2007 | 14.004578485721 | 2006 | 13.974936732062 | 2005 | 13.675246598252 | 2004 | 13.66549884027 | 2003 | 13.755668654285 | 2002 | 13.655818112727 | 2001 | 13.77594300047 | 2000 | 14.036979130937 | 1999 | 13.895438227335 | 1998 | 14.014224247454 | 1997 | 13.952894825707 | 1996 | 14.20188042776 | 1995 | 14.431242088754 | 1994 | 14.831166483096 | 1993 | 15.220784857692 | 1992 | 15.630672864931 | 1991 | 16.020282365528 | 1990 | 16.529834049302 | 1989 | 16.250501222992 | 1988 | 15.851865126458 | 1987 | 15.57206540119 | 1986 | 15.492161092649 | 1985 | 15.711823759804 | 1984 | 15.541135290031 | 1983 | 15.541271949492 | 1982 | 15.82174826744 | 1981 | 15.75119683487 | 1980 | 15.85110114569 | 1979 | 15.580347831857 | 1978 | 15.019000025722 | 1977 | 15.138716847904 | 1976 | 14.697217527769 | 1975 | 14.716144039129 | 1974 | 14.857824167769 | 1973 | 14.876763489568 | 1972 | 15.628716603067 | 1971 | 17.16174245796 | 1970 | 18.306287124996 | 1969 | 17.871800362084 | 1968 | 17.6 | 1967 | 17.837261094175 | 1966 | 18.483726501092 | 1965 | 19.574726728074 | 1964 | 21.310438228527 | 1963 | 21.964140322565 | 1962 | 22.654811485069 | 1961 | 23.544262286965 | 1960 | 23.9715286306 |
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