Year maximum value in 2004 = 100 2006 25.1728356258 2007 24.7785162458 2008 26.7313326641 2009 24.9913184239 2010 27.8839303744 2011 27.2408096742 2012 30.4442166642 2013 30.3170868717 2014 33.3707108156 2015 31.1218666171 2016 32.2972064139 2017 33.1984930686 2018 32.8881444802 2019 33.9198070243 2020 33.0659050704 2021 36.0329182168