Year | Value | 2021 | 13.421320298015 | 2020 | 15.185572507409 | 2019 | 14.218852645178 | 2018 | 12.971271787444 | 2017 | 13.164045506115 | 2016 | 14.555516572556 | 2015 | 15.603162927547 | 2014 | 14.21253564826 | 2013 | 13.388333161459 | 2012 | 12.778639368548 | 2011 | 12.22476095388 | 2010 | 12.157776992818 | 2009 | 14.106708986981 | 2008 | 16.421175368486 | 1999 | 12.733458716325 | 1998 | 12.679334999709 | 1997 | 10.693809961055 | 1996 | 9.8504574398009 | 1995 | 17.95407254663 | 1994 | 25.559167333867 |
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