Year | Value | 2021 | 0.395 | 2019 | 0.367 | 2018 | 0.376 | 2016 | 0.443 | 2013 | 0.376 | 2009 | 0.373 | 2008 | 0.371 | 2007 | 0.373 | 2006 | 0.344 | 2005 | 0.279 | 2003 | 0.262 | 2000 | 0.269 | 1993 | 0.192 | 1992 | 0.185 | 1989 | 0.192 | 1986 | 0.187 | 1985 | 0.192 | 1982 | 0.149 | 1980 | 0.113 | 1975 | 0.049 | 1970 | 0.05 | 1965 | 0.043 | 1960 | 0.017 |
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