Year maximum value in 2004 = 100 2006 16.2406050355 2007 14.7293437557 2008 18.3690516107 2009 20.6139570994 2010 25.6176815296 2011 25.1548660741 2012 20.9551900149 2013 21.9222834872 2014 22.0757895852 2015 29.3648607352 2016 29.6536559386 2017 32.0022092183 2018 24.7554165232 2019 32.5652828261 2020 38.0043442688 2021 37.3784534267