| Year | Value | | 2014 | -93.027219292537 | | 2013 | -90.578352917602 | | 2012 | -99.14236452008 | | 2011 | -104.38866797355 | | 2010 | -111.90134717934 | | 2009 | -102.34625173434 | | 2008 | -104.99188076767 | | 2007 | -114.75249353141 | | 2006 | -119.66055318476 | | 2005 | -121.79880727998 | | 2004 | -126.55166390239 | | 2003 | -118.85882420856 | | 2002 | -106.17722440209 | | 2001 | -130.01612061617 | | 2000 | -130.05006171071 | | 1999 | -121.05659057046 | | 1998 | -130.86551637753 | | 1997 | -137.66649661371 | | 1996 | -130.55146272746 | | 1995 | -123.37145824436 | | 1994 | -125.43434976452 | | 1993 | -118.23920334965 | | 1992 | -117.89298552564 | | 1991 | -119.05670701325 | | 1990 | -120.24735341267 | | 1989 | -123.82323331391 | | 1988 | -106.86696716046 | | 1987 | -98.94223958885 | | 1986 | -114.16805225755 | | 1985 | -117.38581968332 | | 1984 | -111.66083179959 | | 1983 | -95.671789150252 | | 1982 | -103.30280245983 | | 1981 | -125.50375462644 | | 1980 | -196.52344231938 | | 1979 | -233.89754835561 | | 1978 | -199.01784281124 | | 1977 | -234.37076787625 | | 1976 | -246.85024012839 | | 1975 | -224.28100581813 | | 1974 | -299.17679072551 | | 1973 | -281.4263303605 | | 1972 | -261.62519310728 | | 1971 | -227.32194941881 |
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