Year | Value | 2022 | 29.9 | 2021 | 31.7 | 2020 | 34.6 | 2019 | 29.7 | 2018 | 27.8 | 2017 | 27.1 | 2016 | 28.2 | 2015 | 28.8 | 2014 | 27.6 | 2013 | 31.2 | 2012 | 31.4 | 2011 | 34.7 | 2010 | 38.8 | 2009 | 43.2 | 2008 | 42.3 | 2007 | 44.9 | 2006 | 45.8 | 2005 | 50.6 | 2004 | 59 | 2003 | 57.7 | 2000 | 75.9 | 1999 | 67.8 | 1998 | 64.3 | 1995 | 64.4 | 1994 | 64.8 | 1987 | 59.6 |
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