| Year | Value | | 2022 | 10.952240410053 | | 2021 | 16.272798880743 | | 2020 | 12.17484654316 | | 2019 | 16.859820140959 | | 2018 | 15.454482167843 | | 2017 | 14.366219110145 | | 2016 | 11.477460884446 | | 2015 | 11.389851992585 | | 2014 | 8.1430425877135 | | 2013 | 7.3411964303832 | | 2012 | 6.9703317422598 | | 2011 | 0.48605255172777 | | 2010 | 7.7061704377068 | | 2009 | 8.0984258822321 | | 2008 | 26.834782127607 | | 2007 | 16.455164120564 | | 2006 | 1.2047364960346 | | 2005 | 0.98369803348967 | | 2004 | -6.5065995960527 | | 2003 | 1.5283110333219 | | 2002 | 12.439519216111 | | 2001 | 9.3506871670142 | | 2000 | 11.629164087982 | | 1999 | 9.1478406407439 | | 1998 | 9.62050307655 | | 1997 | 5.7050906963136 | | 1996 | 6.1180197090568 | | 1995 | 8.1515779212867 |
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