| Year | Value | | 2021 | 32.96228971 | | 2020 | 31.60419095 | | 2019 | 28.80487199 | | 2018 | 25.5 | | 2017 | 22.5 | | 2016 | 19.9 | | 2015 | 17.6 | | 2014 | 15.56 | | 2013 | 14 | | 2012 | 12.44922872 | | 2011 | 10.8703 | | 2010 | 9.2 | | 2009 | 7.63 | | 2008 | 6.88 | | 2007 | 6.205037419 | | 2006 | 5.237691158 | | 2005 | 3.799001139 | | 2004 | 3.308003478 | | 2003 | 2.436781193 | | 2002 | 1.796779883 | | 2001 | 1.336791166 | | 2000 | 0.921794919 | | 1999 | 0.715827015 | | 1998 | 0.206094461 | | 1997 | 0.051311347 | | 1996 | 0.03550736 | | 1995 | 0.009217541 |
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