Year maximum value in 2004 = 100 2006 4.7306563477 2007 3.9219531944 2008 3.8818966506 2009 4.2239119162 2010 4.5972935331 2011 4.2960270438 2012 4.2958152039 2013 4.7529733834 2014 4.4858031691 2015 4.4858031691 2016 5.1704230388 2017 5.2043385814 2018 5.9226713264 2019 6.3457665475 2020 6.3454311342 2021 5.8940235752