| Year | Value | | 2021 | 75.59261708172 | | 2020 | 73.449231667303 | | 2019 | 68.052644562968 | | 2018 | 62.760786385177 | | 2017 | 59.337101665424 | | 2016 | 56.442520620832 | | 2015 | 53.358129207621 | | 2014 | 47.730216987485 | | 2013 | 45.152264904848 | | 2012 | 42.211139266887 | | 2011 | 38.680678155728 | | 2010 | 34.014552816831 | | 2009 | 30.391535537635 | | 2008 | 25.972928550384 | | 2007 | 23.372304958989 | | 2006 | 20.502279866484 | | 2005 | 16.268029203247 | | 2004 | 14.164038913097 | | 2003 | 10.854002967868 | | 2002 | 8.4866194216437 | | 2001 | 5.0648036901965 | | 2000 | 3.3537577807214 | | 1999 | 1.8330911546948 | | 1998 | 1.1376884925719 | | 1997 | 0.5757134847328 | | 1996 | 0.28763041214677 | | 1995 | 0.093495507138761 | | 1994 | 0.039714697839751 | | 1993 | 0.01901542958814 | | 1992 | 0.0088761260157113 | | 1991 | 0.0024625023344724 |
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