| Year | Value | | 2021 | 4.4677555618136 | | 2020 | 4.4677555618136 | | 2019 | 4.4677555618136 | | 2018 | 4.4677555618136 | | 2017 | 4.4677555618136 | | 2016 | 4.4677555618136 | | 2015 | 4.4677555618136 | | 2014 | 4.4677555618136 | | 2013 | 4.4677555618136 | | 2012 | 4.4677555618136 | | 2011 | 4.4677555618136 | | 2010 | 4.4677555618136 | | 2009 | 4.4566741762884 | | 2008 | 4.4455927907632 | | 2007 | 4.434511405238 | | 2006 | 4.4234300197128 | | 2005 | 4.4123486341876 | | 2004 | 4.4012672486624 | | 2003 | 4.3901858631371 | | 2002 | 4.3791044776119 | | 2001 | 4.3680230920867 | | 2000 | 4.3569417065615 | | 1999 | 4.2662207828781 | | 1998 | 4.1754998591946 | | 1997 | 4.0847789355111 | | 1996 | 3.9940580118276 | | 1995 | 3.9033370881442 | | 1994 | 3.8126161644607 | | 1993 | 3.7218952407773 | | 1992 | 3.6311743170938 | | 1991 | 3.5404533934103 | | 1990 | 3.4497324697268 |
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