Year | Value | 2019 | 0.751 | 2018 | 0.69 | 2017 | 0.882 | 2016 | 0.633 | 2012 | 0.594 | 2011 | 0.564 | 2010 | 0.535 | 2009 | 0.501 | 2008 | 0.487 | 2007 | 0.45 | 2006 | 0.426 | 2005 | 0.389 | 2004 | 0.376 | 2000 | 0.302 | 1999 | 0.297 | 1995 | 0.293 | 1990 | 0.078 | 1989 | 0.081 | 1985 | 0.27 | 1981 | 0.203 | 1970 | 0.114 | 1965 | 0.085 | 1960 | 0.065 |
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