Year maximum value in 2004 = 100 2006 4.9871221104 2007 4.7499286828 2008 1.5091303162 2009 5.1096530384 2010 6.2887776016 2011 6.172932813 2012 6.1954861409 2013 5.9857652924 2014 6.2191639376 2015 6.2292794882 2016 5.6856624246 2017 5.1722672073 2018 5.3161172138 2019 5.9258868493 2020 6.129598168 2021 4.9353261802