Year Number 1996 -1.15118622779846 1998 -1.12271451950073 2000 -1.04199123382568 2002 -1.46213829517365 2003 -1.51878440380096 2004 -1.32268130779266 2005 -1.24752271175385 2006 -1.2592887878418 2007 -1.25203287601471 2008 -1.32310199737549 2009 -1.62521064281464 2010 -1.34115171432495 2011 -1.20131802558899 2012 -1.07890439033508 2013 -1.10128474235535 2014 -1.03973531723022 2015 -1.09781730175018 2016 -0.799367249011993 2017 -0.894905567169189 2018 -0.918106615543365 2019 -0.815560400485992 2020 -0.88781064748764 2021 -1.1222825050354 2022 -1.285315990448