| Year | Value | | 2021 | 11.001980991981 | | 2020 | 10.974160974161 | | 2019 | 10.94653994654 | | 2018 | 10.918621918622 | | 2017 | 10.891000891001 | | 2016 | 10.863082863083 | | 2015 | 10.835461835462 | | 2014 | 10.880379934699 | | 2013 | 10.931730483823 | | 2012 | 10.973309608541 | | 2011 | 11.024614472123 | | 2010 | 11.072635635932 | | 2009 | 11.031188852653 | | 2008 | 10.979976303317 | | 2007 | 10.938566350711 | | 2006 | 10.897156398104 | | 2005 | 10.855746445498 | | 2004 | 10.814336492891 | | 2003 | 10.772926540284 | | 2002 | 10.731516587678 | | 2001 | 10.690106635071 | | 2000 | 10.648696682465 | | 1999 | 10.606723933649 | | 1998 | 10.564751184834 | | 1997 | 10.522778436019 | | 1996 | 10.480805687204 | | 1995 | 10.438832938389 | | 1994 | 10.396860189574 | | 1993 | 10.354887440758 | | 1992 | 10.312914691943 | | 1991 | 10.270941943128 | | 1990 | 10.228969194313 |
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