Year | Value | 2011 | 51.226321570457 | 2010 | 47.098265673964 | 2009 | 43.625743478239 | 2008 | 41.285131468331 | 2007 | 46.303538077024 | 2006 | 49.574610060974 | 2005 | 53.666296568637 | 2002 | 48.475078620009 | 1999 | 55.444980728865 | 1998 | 55.012470832447 | 1997 | 64.462415144609 | 1995 | 68.394915278754 | 1994 | 69.825915522059 | 1993 | 74.12313156115 | 1992 | 70.937868983181 | 1991 | 62.067416275778 | 1990 | 87.196759975914 |
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