Year | Value | 2020 | 2.228 | 2019 | 2.06 | 2018 | 1.888 | 2017 | 1.809 | 2016 | 1.589 | 2015 | 1.496 | 2014 | 1.489 | 2013 | 1.557 | 2012 | 1.305 | 2011 | 1.254 | 2010 | 1.148 | 2009 | 1.082 | 2008 | 0.907 | 2007 | 0.876 | 2006 | 0.828 | 2005 | 0.776 | 2004 | 0.72 | 2003 | 0.735 | 2002 | 0.723 | 2000 | 0.681 | 1999 | 0.683 | 1997 | 0.658 | 1996 | 0.496 | 1995 | 0.478 | 1994 | 0.449 | 1993 | 0.431 | 1992 | 0.411 | 1991 | 0.393 | 1990 | 0.392 | 1989 | 0.374 | 1988 | 0.367 | 1987 | 0.348 | 1986 | 0.335 | 1985 | 0.315 | 1981 | 0.255 | 1980 | 0.255 | 1975 | 0.234 | 1970 | 0.232 | 1965 | 0.161 | 1960 | 0.143 |
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