Year maximum value in 2004 = 100 2006 6.1842732137 2007 6.0337393709 2008 6.7506559005 2009 4.5358838486 2010 4.0211637114 2011 6.0464509544 2012 6.4783286866 2013 8.4458891962 2014 7.7898948613 2015 7.5612287734 2016 7.8472088335 2017 7.2489616976 2018 7.071279667 2019 7.3722204523 2020 7.3708691577 2021 7.4358878441