Year | Value | 2020 | 2.99 | 2019 | 2.84 | 2018 | 2.8 | 2017 | 2.75 | 2016 | 2.69 | 2015 | 2.63 | 2014 | 2.65 | 2013 | 2.64 | 2012 | 2.66 | 2011 | 2.62 | 2010 | 2.74 | 2009 | 2.61 | 2008 | 2.57 | 2007 | 2.53 | 2006 | 2.5 | 2005 | 2.49 | 2004 | 2.46 | 2003 | 2.47 | 2002 | 2.49 | 2001 | 2.16 | 2000 | 2.1 | 1999 | 2.5999999046 | 1998 | 2.5 | 1997 | 2.5 | 1996 | 2.5 | 1995 | 2.5 | 1994 | 2.5 | 1993 | 2.5 | 1992 | 2.4000000954 | 1991 | 2.4000000954 | 1990 | 2.4000000954 | 1989 | 2.0999999046326 | 1988 | 2.0999999046326 | 1987 | 2.0999999046326 | 1986 | 2.0999999046326 | 1985 | 2.0999999046326 | 1980 | 2.2000000476837 | 1975 | 2 |
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