Year | Value | 2021 | 0.67 | 2020 | 0.656 | 2019 | 0.627 | 2018 | 0.573 | 2017 | 0.536 | 2016 | 0.492 | 2015 | 0.481 | 2014 | 0.484 | 2013 | 0.418 | 2012 | 0.397 | 2011 | 0.382 | 2010 | 0.362 | 2009 | 0.353 | 2008 | 0.339 | 2007 | 0.326 | 2006 | 0.313 | 2005 | 0.304 | 2004 | 0.277 | 2003 | 0.268 | 2001 | 0.247 | 1997 | 0.2 | 1995 | 0.201 | 1991 | 0.188 | 1990 | 0.177 | 1986 | 0.144 | 1985 | 0.154 | 1980 | 0.12 | 1970 | 0.119 | 1965 | 0.123 |
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