Year maximum value in 2004 = 100 2006 5.1930177726 2007 4.069604485 2008 6.2498936208 2009 4.9682149637 2010 4.8430530761 2011 5.8011277338 2012 5.3971352215 2013 4.1834434759 2014 4.5010552087 2015 5.0580999474 2016 4.828645253 2017 5.9937333531 2018 5.895069048 2019 5.8177707026 2020 4.2314954429 2021 4.2289533634