Year | Value | 2021 | 7.16 | 2020 | 7.11 | 2019 | 8.37 | 2018 | 6.76 | 2017 | 6.67 | 2016 | 6.48 | 2015 | 6.35 | 2014 | 6.31 | 2013 | 6.4 | 2012 | 7.12 | 2011 | 7.11 | 2010 | 7.31 | 2009 | 7.53 | 2008 | 7.62 | 2007 | 8.06 | 2006 | 8.46 | 2005 | 8.85 | 2004 | 9.3 | 2003 | 8.47 | 2002 | 8.3 | 2001 | 9.65 | 2000 | 9.45 | 1999 | 9.74 | 1997 | 10.72 | 1996 | 14.8 | 1993 | 16.41 | 1991 | 11.33 | 1990 | 11.63 | 1988 | 13.52 |
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