| Year | Value | | 2021 | 67.509728 | | 2020 | 65.54188027 | | 2019 | 63.62841477 | | 2018 | 61.80553132 | | 2017 | 59.9506309 | | 2016 | 54 | | 2015 | 51.20542499 | | 2014 | 44.92 | | 2013 | 44.03 | | 2012 | 40.30189522 | | 2011 | 42.7 | | 2010 | 40.1 | | 2009 | 39.08 | | 2008 | 33.82 | | 2007 | 22.29 | | 2006 | 17.34956617 | | 2005 | 11.48400928 | | 2004 | 11.14086254 | | 2003 | 9.987424077 | | 2002 | 8.518077815 | | 2001 | 7.268399878 | | 2000 | 6.554796477 | | 1999 | 3.836864509 | | 1998 | 2.750648071 | | 1997 | 0.539065541 | | 1996 | 0.219998526 | | 1995 | 0.056123043 | | 1994 | 0.007636899 |
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