| Year | Value | | 2020 | 0.47694417777208 | | 2019 | 0.69971367716331 | | 2018 | 0.71844345958828 | | 2017 | 0.75260599232417 | | 2016 | 0.77470123138369 | | 2015 | 0.80386439538436 | | 2014 | 0.71309083770556 | | 2013 | 0.47727250046968 | | 2012 | 0.8957090163861 | | 2011 | 0.14595097780314 | | 2010 | 0.092804711509594 | | 2009 | 0.095210620173417 | | 2000 | 3.1613775766018 | | 1999 | 3.2914572202722 | | 1998 | 15.438971119518 | | 1997 | 16.114315671566 | | 1996 | 16.708760365929 | | 1995 | 17.341080557412 |
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