Year maximum value in 2004 = 100 2006 38.6437783224 2007 39.418994319 2008 39.6414812798 2009 37.1635223925 2010 38.6497433883 2011 39.4796516864 2012 40.2350589938 2013 47.7635830395 2014 46.9604546438 2015 52.4528228858 2016 61.7733368696 2017 63.6513107836 2018 63.6228100833 2019 62.1746427662 2020 71.9926071706 2021 70.6781062229