| Year | Value | | 2021 | 21.23153129 | | 2020 | 18.05191463 | | 2019 | 16.8 | | 2018 | 14.2999971 | | 2017 | 12.2 | | 2016 | 10.3 | | 2015 | 8.8 | | 2014 | 6.5 | | 2013 | 4.8 | | 2012 | 4.1 | | 2011 | 3.5 | | 2010 | 3 | | 2009 | 2.5 | | 2008 | 2.2 | | 2007 | 1.9 | | 2006 | 1.6 | | 2005 | 1.3 | | 2004 | 1.1 | | 2003 | 0.980483039 | | 2002 | 0.477750907 | | 2001 | 0.233129556 | | 2000 | 0.191071643 | | 1999 | 0.147053172 | | 1998 | 0.030226183 | | 1997 | 0.009329658 | | 1996 | 0.009069176 | | 1995 | 0.008783623 | | 1994 | 0.006776105 |
|