| Year | Value | | 2014 | -168.09339324975 | | 2013 | -211.39727937126 | | 2012 | -248.41581886811 | | 2011 | -338.60393744945 | | 2010 | -297.58531071841 | | 2009 | -131.59563241625 | | 2008 | -58.858516979492 | | 2007 | -44.771292997664 | | 2006 | -29.662195845837 | | 2005 | -28.457354028579 | | 2004 | 19.696471537381 | | 2003 | 18.975880953041 | | 2002 | 17.970636932058 | | 2001 | 19.079488724482 | | 2000 | 18.692282528328 | | 1999 | 18.5645022571 | | 1998 | 17.581318181636 | | 1997 | 19.011898882439 | | 1996 | 17.894798521114 | | 1995 | 16.632044174292 | | 1994 | 14.244097799641 | | 1993 | 18.464668919585 | | 1992 | 13.401893006308 | | 1991 | 14.995180218927 | | 1990 | 19.591416753269 | | 1989 | 14.15542543089 | | 1988 | 13.538746907947 | | 1987 | 16.352673127346 | | 1986 | 20.508238518035 | | 1985 | 20.458928185378 |
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