Year | Value | 2020 | 2.508 | 2019 | 2.457 | 2018 | 2.385 | 2017 | 2.342 | 2016 | 2.289 | 2015 | 2.242 | 2014 | 2.209 | 2013 | 2.174 | 2012 | 2.098 | 2011 | 2.062 | 2010 | 2.014 | 2009 | 1.949 | 2008 | 1.871 | 2007 | 1.752 | 2006 | 1.7 | 2005 | 1.636 | 2004 | 1.576 | 2003 | 1.579 | 2002 | 1.499 | 2001 | 1.396 | 2000 | 1.302 | 1999 | 1.315 | 1998 | 1.269 | 1997 | 1.233 | 1996 | 1.169 | 1995 | 1.116 | 1994 | 1.057 | 1993 | 1.012 | 1992 | 0.948 | 1991 | 0.875 | 1990 | 0.811 | 1989 | 0.8 | 1988 | 0.7 | 1987 | 0.7 | 1986 | 0.6 | 1985 | 0.6 | 1984 | 0.6 | 1983 | 0.5 | 1982 | 0.5 | 1981 | 0.5 |
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