Year | Value | 2021 | 0.6 | 2020 | 0.7 | 2019 | 0.6 | 2018 | 0.9 | 2017 | 0.8 | 2016 | 1 | 2015 | 0.8 | 2014 | 1.4 | 2013 | 1.8 | 2012 | 2.3 | 2011 | 2.1 | 2010 | 3.9 | 2009 | 4.5 | 2008 | 5.3 | 2007 | 6.7 | 2006 | 8.7 | 2004 | 12.2 | 2002 | 16.4 | 2000 | 23.5 | 1999 | 22.9 | 1998 | 19.1 | 1996 | 19.8 | 1994 | 24.8 | 1992 | 34.4 | 1990 | 41 | 1988 | 45.3 | 1981 | 48 |
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