Year Number 1996 -1.64815735816956 1998 -1.53362345695496 2000 -1.3816899061203 2002 -1.08354067802429 2003 -1.06657803058624 2004 -1.18313717842102 2005 -1.10024237632751 2006 -1.18217408657074 2007 -1.29604709148407 2008 -1.29554963111877 2009 -1.27246570587158 2010 -1.21289575099945 2011 -1.23239934444427 2012 -1.2076199054718 2013 -1.26313161849976 2014 -1.01177895069122 2015 -1.07439470291138 2016 -1.16580295562744 2017 -1.37690246105194 2018 -1.30321049690247 2019 -1.25325226783752 2020 -1.24842262268066 2021 -1.20692694187164 2022 -1.25580060482025