Year | Value | 2018 | 0.664 | 2017 | 0.975 | 2016 | 0.941 | 2015 | 0.92 | 2014 | 0.885 | 2013 | 0.89 | 2012 | 0.854 | 2011 | 0.808 | 2010 | 0.724 | 2009 | 0.7 | 2008 | 0.646 | 2007 | 0.525 | 2006 | 0.491 | 2005 | 0.498 | 2003 | 0.384 | 1997 | 0.856 | 1995 | 0.82 | 1990 | 0.657 | 1988 | 0.471 | 1984 | 0.637 | 1981 | 0.426 | 1980 | 0.416 | 1975 | 0.46 | 1970 | 0.453 | 1965 | 0.378 | 1960 | 0.34 |
|