Year Number 1996 0.333532422780991 1998 0.339321404695511 2000 0.390961945056915 2002 0.336637645959854 2003 0.31748366355896 2004 0.573030769824982 2005 0.533180177211761 2006 0.631312012672424 2007 0.543636023998261 2008 0.573908567428589 2009 0.589427828788757 2010 0.495849043130875 2011 0.51117467880249 2012 0.640056967735291 2013 0.618955671787262 2014 0.558731198310852 2015 0.595008313655853 2016 0.633674025535584 2017 0.608596861362457 2018 0.579138517379761 2019 0.731873512268066 2020 0.742793262004852 2021 0.730730891227722 2022 0.721560716629028