| Year | Value | | 2023 | 10.3971874765 | | 2022 | 13.795488743252 | | 2021 | 5.0523287609658 | | 2020 | 2.6310731118474 | | 2019 | 3.8278543259944 | | 2018 | 4.6254844313778 | | 2017 | 1.3390212110439 | | 2016 | -1.544796668139 | | 2015 | 0.5941564374952 | | 2014 | 1.068309876843 | | 2013 | 3.9847123554813 | | 2012 | 3.3349226769344 | | 2011 | 5.7892532881588 | | 2010 | 6.0914166860189 | | 2009 | 5.5874200426439 | | 2008 | 7.8508025571448 | | 2007 | 4.8373292831399 | | 2006 | 6.5585141227698 | | 2005 | 9.0149128334384 | | 2004 | 11.87436359364 | | 2003 | 15.273488993626 | | 2002 | 22.539886260539 | | 2001 | 34.477012349353 | | 2000 | 45.666594044024 | | 1999 | 45.803781132636 | | 1998 | 59.096582754117 | | 1997 | 154.76348043631 | | 1996 | 38.829301338285 | | 1995 | 32.24248472576 | | 1994 | 136.75939281544 | | 1993 | 255.1668618267 | | 1992 | 211.20558761008 | | 1991 | 230.62249490018 |
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