Year Number 2004 -0.423489183187485 2005 -0.457559108734131 2006 -0.468085944652557 2007 -0.660639941692352 2008 -0.69921886920929 2009 -0.80252867937088 2010 -0.880354702472687 2011 -0.783309817314148 2012 -0.799028694629669 2013 -0.772437751293182 2014 -0.566529631614685 2015 -0.379997193813324 2016 -0.299741595983505 2017 -0.0621311701834202 2018 -0.0640199407935143 2019 -0.0515526756644249 2020 0.135919511318207 2021 0.0944074466824532 2022 0.167575597763062