Year maximum value in 2004 = 100 2006 5.6817295252 2007 6.3834878503 2008 6.6496440573 2009 5.4994162592 2010 4.7365772779 2011 5.8742133087 2012 7.5100049621 2013 8.2312587352 2014 7.391609094 2015 7.4843968356 2016 7.6523243271 2017 6.8284221233 2018 6.3800219856 2019 6.5278900126 2020 6.5242569573 2021 5.1756173924