Year | Value | 2014 | 40.859375405283 | 2013 | 39.748991664502 | 2012 | 43.329659153105 | 2011 | 48.511423850046 | 2010 | 46.806605485718 | 2009 | 47.332139027563 | 2008 | 46.602059357965 | 2007 | 49.363530307436 | 2006 | 48.21781842914 | 2005 | 47.936634745698 | 2004 | 47.541653141574 | 2003 | 48.08149086739 | 2002 | 46.719169980905 | 2001 | 48.366633301702 | 2000 | 46.407582509018 | 1999 | 47.036460364937 | 1998 | 43.882954228661 | 1997 | 39.485376017383 | 1996 | 37.787730594145 | 1995 | 37.334330196225 | 1994 | 35.161801790644 | 1993 | 32.688084456226 | 1992 | 32.497590859031 | 1991 | 28.918889780328 | 1990 | 29.622683000033 | 1989 | 30.663195185368 | 1988 | 36.37733737832 | 1987 | 37.844308062032 | 1986 | 37.942079232528 | 1985 | 33.146141881662 | 1984 | 34.358109845031 | 1983 | 40.661882969399 | 1982 | 40.009738336481 | 1981 | 41.19662305809 | 1980 | 40.836639498449 | 1979 | 37.357989221927 | 1978 | 47.048446201585 | 1977 | 49.685107302625 | 1976 | 44.585702809213 | 1975 | 43.400213631249 | 1974 | 44.06160971804 | 1973 | 43.476691644625 | 1972 | 41.057499644349 | 1971 | 41.3847906453 |
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