Year maximum value in 2004 = 100 2006 26.3716182217 2007 29.6366789682 2008 33.1865023922 2009 32.8423800076 2010 35.9977681732 2011 39.8510538748 2012 42.511551964 2013 43.4136545796 2014 42.4348955771 2015 50.3897000777 2016 47.5068360076 2017 47.8769957005 2018 47.3881427344 2019 50.0015967653 2020 50.0396510643 2021 51.5962899016