Year | Value | 2021 | 22.245980822086 | 2020 | 22.274646223455 | 2019 | 21.098550997951 | 2018 | 21.740494569157 | 2017 | 23.933496314196 | 2016 | 21.630055322765 | 2015 | 26.31109885125 | 2014 | 27.092829966042 | 2013 | 26.740390630359 | 2012 | 28.036577661604 | 2011 | 24.045326160706 | 2010 | 23.883364205695 | 2009 | 27.686814021982 | 2008 | 27.920899875318 | 2007 | 26.617456273108 | 2006 | 27.526440240407 | 1996 | 14.937107893937 | 1995 | 16.765795854875 | 1994 | 19.916743917583 | 1993 | 23.684799219865 | 1992 | 27.845540072474 | 1991 | 25.557193488693 | 1990 | 27.501612937532 |
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