Year | Value | 2022 | 21.087776697611 | 2021 | 21.071106184011 | 2020 | 24.31040999883 | 2019 | 22.201655971967 | 2018 | 23.023749154806 | 2017 | 23.257402201957 | 2016 | 22.737568851359 | 2015 | 23.191295653504 | 2014 | 22.213413321583 | 2013 | 21.840101541737 | 2012 | 23.885431470386 | 2011 | 22.456203959879 | 2010 | 22.122194111402 | 2009 | 30.256372833431 | 2008 | 23.197116419177 | 2007 | 21.080512815442 | 2006 | 19.173654764908 | 2005 | 23.367842970994 | 2004 | 20.696362733823 | 2003 | 20.928757320455 | 2002 | 20.182038851429 | 2001 | 19.16241758862 | 2000 | 18.357298125409 | 1999 | 12.558831444281 | 1998 | 15.959832276332 | 1997 | 13.945145652767 | 1996 | 12.22291129927 | 1995 | 12.874584021972 |
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