Year | Value | 2021 | 21.485124158301 | 2020 | 22.865013398644 | 2019 | 22.364056255432 | 2018 | 22.53453880232 | 2017 | 22.881297521459 | 2016 | 23.0674566943 | 2015 | 23.235128011375 | 2014 | 23.018422325796 | 2013 | 22.867986234669 | 2012 | 22.867797986601 | 2011 | 21.041507800667 | 2010 | 22.587625954185 | 2009 | 23.294265597658 | 2008 | 23.25921477123 | 2007 | 21.382129631622 | 2006 | 19.809702108517 | 2005 | 19.8994457438 | 2004 | 20.362671653357 | 2003 | 20.661613838068 | 2002 | 20.893050700938 | 2001 | 21.399657113912 | 2000 | 22.378462647849 | 1999 | 21.802165164374 | 1998 | 20.765237888853 | 1997 | 20.93471548102 | 1996 | 22.916078432474 | 1995 | 23.167205318683 | 1994 | 24.194785399341 | 1993 | 25.010490126343 | 1992 | 24.07442466685 | 1991 | 25.549530208957 |
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