Year | Value | 2021 | 2.973 | 2020 | 2.808 | 2019 | 2.649 | 2018 | 2.595 | 2017 | 2.455 | 2016 | 2.31 | 2015 | 2.159 | 2014 | 2.036 | 2013 | 1.887 | 2012 | 1.753 | 2011 | 1.591 | 2010 | 1.438 | 2009 | 1.033 | 2008 | 1.042 | 2007 | 1.039 | 2006 | 1.042 | 2005 | 0.981 | 2004 | 0.984 | 2003 | 0.946 | 2002 | 0.892 | 1992 | 0.99 | 1991 | 1.066 | 1990 | 1.1 | 1984 | 0.817 | 1979 | 0.516 | 1970 | 0.463 | 1965 | 0.473 | 1960 | 0.559 |
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