| Year | Value | | 2014 | 49.544661483926 | | 2013 | 55.471601870254 | | 2012 | 57.697465948808 | | 2011 | 51.047371971339 | | 2010 | 53.880701581074 | | 2009 | 58.657746693232 | | 2008 | 64.042648629022 | | 2007 | 55.177699055479 | | 2006 | 49.469505864333 | | 2005 | 48.555682951553 | | 2004 | 45.39361078431 | | 2003 | 50.196963309402 | | 2002 | 52.236191797451 | | 2001 | 39.960871297932 | | 2000 | 40.943013221057 | | 1999 | 46.064883036027 | | 1998 | 59.665211194399 | | 1997 | 51.368144383684 | | 1996 | 52.161778792012 | | 1995 | 47.20474463806 | | 1994 | 47.558607065594 | | 1993 | 59.217199544742 | | 1992 | 63.490439003524 | | 1991 | 64.088920450569 | | 1990 | 66.578290509101 |
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