| Year | Value | | 2014 | -164.53920470097 | | 2013 | -178.49929114144 | | 2012 | -180.63802491242 | | 2011 | -186.09607518889 | | 2010 | -178.60956584577 | | 2009 | -182.79854683364 | | 2008 | -214.99289608781 | | 2007 | -224.67677010706 | | 2006 | -238.90908965792 | | 2005 | -255.4225843458 | | 2004 | -258.61860625919 | | 2003 | -256.86165111682 | | 2002 | -238.09800563726 | | 2001 | -267.79414428618 | | 2000 | -296.43664589318 | | 1999 | -282.56063107947 | | 1998 | -291.77000116161 | | 1997 | -276.43669055355 | | 1996 | -270.3254241164 | | 1995 | -279.4162414895 | | 1994 | -282.05385730437 | | 1993 | -300.61757024848 | | 1992 | -308.63151764619 | | 1991 | -317.16976814115 | | 1990 | -331.876805393 | | 1989 | -300.57971283107 | | 1988 | -296.35354966998 | | 1987 | -275.80257718668 | | 1986 | -302.58881895533 | | 1985 | -256.9962652482 | | 1984 | -307.03758846759 | | 1983 | -307.48960426441 | | 1982 | -376.90542092871 | | 1981 | -570.32868543279 | | 1980 | -795.30124614226 | | 1979 | -970.37243648012 | | 1978 | -1,024.3137316075 | | 1977 | -1,206.3852876526 | | 1976 | -1,291.0469160895 | | 1975 | -1,237.5429726615 | | 1974 | -1,463.6531692401 | | 1973 | -1,585.9002752541 | | 1972 | -1,539.1923976146 | | 1971 | -1,481.6105912081 |
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