Year Number 1996 0.103578582406044 1998 0.363668382167816 2000 0.245814546942711 2002 0.0557754337787628 2003 0.015878489241004 2004 0.0306956954300404 2005 0.269054442644119 2006 0.280463099479675 2007 0.329305052757263 2008 0.269334226846695 2009 0.288754820823669 2010 0.312994033098221 2011 0.393024772405624 2012 0.450981587171555 2013 0.463030308485031 2014 0.432501822710037 2015 0.273797631263733 2016 0.193467319011688 2017 0.0435318350791931 2018 0.01624720916152 2019 -0.0204177498817444 2020 -0.0247927252203226 2021 -0.100666180253029 2022 -0.244638904929161