Year Number 1996 -0.5208500623703 1998 -0.490328997373581 2000 -0.62007862329483 2002 -0.756493151187897 2003 -0.705886006355286 2004 -0.666135549545288 2005 -0.709110260009766 2006 -0.655459582805634 2007 -0.529211044311523 2008 -0.624475121498108 2009 -0.664479374885559 2010 -0.582948446273804 2011 -0.578526675701141 2012 -0.540134847164154 2013 -0.477090716362 2014 -0.35801687836647 2015 -0.393306106328964 2016 -0.401780694723129 2017 -0.390950411558151 2018 -0.493594706058502 2019 -0.441803723573685 2020 -0.398768901824951 2021 -0.324745863676071 2022 -0.300569444894791