| Year | Value | | 2021 | 0.075143207071597 | | 2020 | 0.0092215173599353 | | 2019 | 0.055789368308629 | | 2018 | 0.097604801685858 | | 2017 | 0.075502460791833 | | 2016 | 0.10126471130013 | | 2015 | 0.057211641172311 | | 2014 | 0.046845597729341 | | 2013 | 0.046761493376893 | | 2012 | 0.029407417443679 | | 2011 | 0.030686017730787 | | 2010 | 0.54910820937182 | | 2009 | 1.0537077710697 | | 2008 | 0.91997507091942 | | 2007 | 0.90679739877595 | | 2004 | 0.61587578293169 | | 2003 | 1.965888306349 | | 2002 | 1.8202460401509 | | 2001 | 2.0120499919802 | | 2000 | 2.0511861498183 | | 1999 | 2.285454108794 | | 1998 | 2.7186735232489 | | 1997 | 3.5729353318733 | | 1996 | 4.122693710408 | | 1995 | 4.4719321834873 | | 1994 | 7.5711513583441 |
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