Year Number 1996 -0.0711131766438484 1998 -0.730146408081055 2000 -1.16382563114166 2002 -1.71746289730072 2003 -1.89185237884521 2004 -2.14913845062256 2005 -2.09840488433838 2006 -1.89445018768311 2007 -1.88537847995758 2008 -1.83428740501404 2009 -1.62008118629456 2010 -1.58397114276886 2011 -1.41644358634949 2012 -1.38123226165771 2013 -1.12914609909058 2014 -0.724599540233612 2015 -0.997430026531219 2016 -0.846989989280701 2017 -0.58410120010376 2018 -0.542416572570801 2019 -0.452942907810211 2020 -0.180229142308235 2021 -0.188807815313339 2022 -0.251907497644424