Year | Value | 2022 | 9.5 | 2021 | 10.9 | 2020 | 14.4 | 2019 | 9.9 | 2018 | 9.7 | 2017 | 8.9 | 2016 | 9.5 | 2015 | 9.5 | 2014 | 8.7 | 2013 | 10.2 | 2012 | 11.7 | 2011 | 12.3 | 2010 | 15.1 | 2009 | 17.7 | 2008 | 18.5 | 2007 | 19.6 | 2006 | 20.1 | 2005 | 25.5 | 2004 | 32.4 | 2003 | 30.7 | 2000 | 50.2 | 1999 | 40.5 | 1998 | 35.9 | 1995 | 32.7 | 1994 | 35 | 1987 | 32.7 |
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