Year Number 1996 -1.78331053256989 1998 -1.87890470027924 2000 -1.43257737159729 2002 -1.63456511497498 2003 -1.75440907478333 2004 -1.35918843746185 2005 -0.913666009902954 2006 -1.1264134645462 2007 -1.15058553218842 2008 -1.09584629535675 2009 -1.19691348075867 2010 -1.25936758518219 2011 -1.36056065559387 2012 -1.32504332065582 2013 -1.20237147808075 2014 -1.19053518772125 2015 -1.09078657627106 2016 -1.09974193572998 2017 -0.919614136219025 2018 -0.842121779918671 2019 -1.05582988262177 2020 -0.847814321517944 2021 -0.992437243461609 2022 -0.741771519184113