Year maximum value in 2004 = 100 2006 24.5253019058 2007 25.8933622123 2008 23.5348827696 2009 27.1168604641 2010 26.2849252569 2011 35.6222841519 2012 35.1877821098 2013 35.101376901 2014 38.7924016857 2015 37.3877940352 2016 37.4882125224 2017 40.117535113 2018 41.9135848433 2019 43.173141922 2020 33.1775818259 2021 41.5526769385