Year | Value | 2021 | 3.412 | 2019 | 4.108 | 2018 | 3.849 | 2017 | 3.15 | 2015 | 2.487 | 2011 | 1.712 | 2010 | 1.703 | 2009 | 1.422 | 2007 | 1.114 | 2006 | 1.156 | 2003 | 0.767 | 2002 | 0.783 | 2001 | 0.922 | 2000 | 0.957 | 1999 | 0.882 | 1998 | 0.896 | 1997 | 0.72 | 1996 | 0.729 | 1995 | 0.905 | 1994 | 0.788 | 1993 | 0.658 | 1991 | 0.732 | 1990 | 0.72 | 1984 | 1.043 | 1981 | 0.673 | 1980 | 0.726 | 1975 | 0.454 | 1970 | 0.445 | 1965 | 0.262 | 1960 | 0.418 |
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