Year | Value | 2022 | 8.6 | 2021 | 8.9 | 2020 | 10.3 | 2019 | 10.8 | 2018 | 11.4 | 2017 | 12.5 | 2016 | 13.8 | 2015 | 14.5 | 2014 | 14.3 | 2013 | 14.8 | 2012 | 16.4 | 2011 | 17.4 | 2010 | 19.1 | 2009 | 20.5 | 2008 | 20.6 | 2007 | 25 | 2006 | 28.9 | 2005 | 32.6 | 2004 | 36.1 | 2003 | 41 | 2002 | 42.6 | 2001 | 45.6 | 2000 | 48.7 | 1999 | 52.4 | 1998 | 44.7 | 1997 | 44.2 | 1996 | 46.6 | 1995 | 42.8 | 1994 | 48.2 | 1993 | 44.2 | 1992 | 38.5 | 1991 | 34.2 | 1990 | 31.6 |
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