Year maximum value in 2004 = 100 2006 19.3024965529 2007 22.8960218579 2008 28.7499056349 2009 26.419423631 2010 27.9264050753 2011 31.8180718648 2012 46.001104389 2013 46.8225106714 2014 46.9700196669 2015 53.1217085969 2016 42.8443188085 2017 44.758409404 2018 43.5123570599 2019 37.4231312627 2020 34.6082954769 2021 31.655448741