Year Number 1996 -1.3873907327652 1998 -1.42518937587738 2000 -1.45503640174866 2002 -1.7139093875885 2003 -1.73716354370117 2004 -1.72932910919189 2005 -1.66308867931366 2006 -1.41297435760498 2007 -1.34994995594025 2008 -1.285773396492 2009 -1.33430373668671 2010 -1.38317584991455 2011 -1.418013215065 2012 -1.33210027217865 2013 -1.30045402050018 2014 -1.18039405345917 2015 -1.19614708423615 2016 -1.01366877555847 2017 -1.09687674045563 2018 -1.06164228916168 2019 -0.975454747676849 2020 -1.03267776966095 2021 -1.2622035741806 2022 -1.37736070156097