Year | Value | 2021 | 27.711258930771 | 2020 | 27.884520642428 | 2019 | 28.147710196339 | 2018 | 28.140703517588 | 2017 | 28.213490452638 | 2016 | 28.000669990344 | 2015 | 27.9705189725 | 2014 | 27.895828509211 | 2013 | 27.400102509512 | 2012 | 27.215511165654 | 2011 | 27.248533832734 | 2010 | 27.279179111098 | 2009 | 27.324074165344 | 2008 | 27.185537845857 | 2007 | 27.200457365907 | 2006 | 27.303552418878 | 2005 | 27.322970128135 | 2004 | 27.354978675147 | 2003 | 27.45703213592 | 2002 | 27.688348313111 | 2001 | 28.401135848238 | 2000 | 30.234461271494 | 1999 | 30.477974708507 | 1998 | 30.503527602069 | 1997 | 30.440462399251 | 1996 | 30.711743421377 | 1995 | 30.71948261924 | 1994 | 30.68346493952 | 1993 | 30.084971314788 | 1992 | 29.981077032248 |
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