Year | Value | 2016 | 1.186 | 2014 | 1.446 | 2010 | 1.397 | 2009 | 1.371 | 2008 | 1.43 | 2007 | 1.429 | 2005 | 1.52 | 2004 | 1.432 | 2003 | 1.39 | 2002 | 1.461 | 2000 | 1.374 | 1999 | 1.345 | 1998 | 1.348 | 1997 | 1.303 | 1990 | 0.835 | 1989 | 0.863 | 1987 | 0.783 | 1986 | 0.807 | 1981 | 0.463 | 1980 | 0.446 | 1975 | 0.256 | 1970 | 0.259 | 1965 | 0.185 | 1960 | 0.216 |
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