Year maximum value in 2004 = 100 2006 29.7507991906 2007 22.714187685 2008 28.0973116025 2009 25.5683819107 2010 25.5667984802 2011 38.1936999736 2012 38.7349219847 2013 43.7204805851 2014 42.9997365947 2015 42.9102165412 2016 44.3347424126 2017 47.1412900372 2018 46.9945201589 2019 47.4982570108 2020 46.5399267691 2021 45.8153042356