Year | Value | 2021 | 13.2 | 2020 | 13.55 | 2019 | 13.43 | 2018 | 13.46 | 2017 | 13.41 | 2016 | 13.56 | 2015 | 13.66 | 2014 | 13.74 | 2013 | 14.81 | 2012 | 13.75 | 2011 | 13.47 | 2010 | 13.34 | 2009 | 13.32 | 2008 | 13.08 | 2007 | 12.15 | 2006 | 12.1 | 2005 | 12.29 | 2004 | 13.18 | 2003 | 14.39 | 2002 | 14.73 | 2001 | 15 | 2000 | 16.7 | 1999 | 15.89 | 1998 | 17.15 | 1997 | 14.42 | 1996 | 14.8 | 1995 | 13.23 | 1994 | 14.46 | 1993 | 15.73 | 1992 | 23.45 | 1991 | 27.53 | 1990 | 33.5 | 1989 | 42.92 |
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