Year | Value | 2020 | 2.441 | 2019 | 2.474 | 2018 | 2.467 | 2017 | 2.42 | 2016 | 2.359 | 2015 | 2.358 | 2014 | 2.256 | 2013 | 2.184 | 2012 | 2.14 | 2011 | 2.129 | 2010 | 2.026 | 2009 | 2.004 | 2008 | 1.97 | 2007 | 1.937 | 2006 | 1.893 | 2005 | 1.775 | 2004 | 1.662 | 2003 | 1.589 | 2002 | 1.538 | 2001 | 1.53 | 2000 | 1.644 | 1999 | 1.732 | 1998 | 1.73 | 1997 | 1.717 | 1996 | 1.68 | 1995 | 1.685 | 1994 | 1.597 | 1993 | 1.499 | 1992 | 1.35 | 1991 | 1.193 | 1990 | 1.002 |
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