Year | Value | 2022 | 20.512517615863 | 2021 | 23.196022847445 | 2020 | 21.925871634362 | 2019 | 21.110232234372 | 2018 | 22.520834589431 | 2017 | 23.959795199088 | 2016 | 24.37195340199 | 2015 | 21.799979984146 | 2014 | 21.818268848034 | 2013 | 23.427936214277 | 2012 | 19.830418536995 | 2011 | 24.247251978383 | 2010 | 23.360560741442 | 2009 | 20.967923925163 | 2008 | 22.925053094478 | 2007 | 25.594766769122 | 2006 | 23.140505792817 | 2005 | 20.354618533912 | 2004 | 20.035855387855 | 2003 | 21.002728444389 | 2002 | 26.908204257062 | 2001 | 17.73943853344 | 2000 | 14.777881433279 | 1999 | 20.664189371209 | 1998 | 21.619394578567 | 1997 | 17.457686647041 | 1996 | 21.552627801536 | 1995 | 19.774199312675 |
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