| Year | Value | | 2021 | 22.067738530891 | | 2020 | -8.0769765767584 | | 2019 | 6.721969080744 | | 2018 | 4.427965955676 | | 2017 | 6.95705222791 | | 2016 | -1.1865824436999 | | 2015 | 12.090652609066 | | 2014 | 0.022499741828668 | | 2013 | 10.262183892237 | | 2012 | 2.3807880176167 | | 2011 | 8.8092274837502 | | 2010 | 10.504174718063 | | 2009 | 0.20205190616103 | | 2008 | -1.9844495559717 | | 2007 | 0.12150049429123 | | 2006 | 0.022353827658989 | | 2005 | 7.5349498080703 | | 2004 | 6.206059918493 | | 2003 | 4.934753079781 | | 2002 | 0.89131226606494 | | 2001 | -1.3132726343811 | | 2000 | -10.11827240694 | | 1999 | -3.0132615858434 | | 1998 | 3.569740856899 | | 1997 | 13.647306401062 | | 1996 | 9.6486749496705 | | 1995 | 0.3253525527618 | | 1994 | -1.5301567062065 | | 1993 | 13.284965066722 | | 1992 | 20.459547719123 | | 1991 | -4.4768721891758 |
|