Year | Value | 2015 | 45.333785025636 | 2014 | 46.197275514046 | 2013 | 45.30505616412 | 2012 | 49.01078210859 | 2011 | 51.154918072064 | 2010 | 52.235433931489 | 2009 | 50.279074231582 | 2008 | 53.353573214388 | 2007 | 56.167149150587 | 2006 | 51.324112197962 | 2005 | 51.459986970515 | 2004 | 57.412209372385 | 2003 | 56.808486917946 | 2002 | 53.963402654278 | 2001 | 53.781972210007 | 2000 | 53.922885851866 | 1999 | 52.547615848773 | 1998 | 58.27799167596 | 1997 | 53.383312314087 | 1996 | 56.236998808477 | 1995 | 54.496864710342 | 1994 | 57.2256188602 | 1993 | 58.49549694153 | 1992 | 55.321746505943 | 1991 | 61.206942270726 | 1990 | 57.432772714993 | 1989 | 59.214765852565 | 1988 | 59.468455994701 | 1987 | 63.635832385253 | 1986 | 58.01600012461 | 1985 | 59.835714024155 | 1984 | 56.07655799387 | 1983 | 56.54897825192 | 1982 | 56.477895542887 | 1981 | 62.157329649221 | 1980 | 71.898924802784 | 1979 | 72.801004562086 | 1978 | 75.908813301097 | 1977 | 76.374513907705 | 1976 | 80.262593141195 | 1975 | 77.822518633564 | 1974 | 75.754378156555 |
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