Year | Value | 2014 | 44.499964660773 | 2013 | 44.581633191654 | 2012 | 42.452979328759 | 2011 | 53.845796975941 | 2010 | 50.901387145884 | 2009 | 53.928145270634 | 2008 | 52.882335959909 | 2007 | 52.921943066054 | 2006 | 47.861148870384 | 2005 | 45.833076600366 | 2004 | 46.34491041008 | 2003 | 46.433404907925 | 2002 | 42.055286096852 | 2001 | 41.243475962915 | 2000 | 40.021132734628 | 1999 | 37.715887114518 | 1998 | 36.25371917035 | 1997 | 35.822825735532 | 1996 | 33.9265138816 | 1995 | 30.068740512683 | 1994 | 27.845145458289 | 1993 | 29.987700443035 | 1992 | 30.626801248469 | 1991 | 27.915294587925 | 1990 | 28.695560099254 | 1989 | 25.399498940719 | 1988 | 24.212730090541 | 1987 | 25.319999701359 | 1986 | 24.34641770718 | 1985 | 22.293411712769 | 1984 | 22.708257403119 | 1983 | 22.666803585092 | 1982 | 22.162341881768 | 1981 | 22.64019948433 |
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