Year Number 1996 0.360743492841721 1998 0.465829730033875 2000 0.320122689008713 2002 0.582995772361755 2003 0.224924057722092 2004 0.230400413274765 2005 0.142397329211235 2006 0.173593416810036 2007 0.0460881590843201 2008 0.376434057950974 2009 0.241088286042213 2010 0.213284954428673 2011 0.0923139303922653 2012 0.155978977680206 2013 0.164272174239159 2014 0.0766165852546692 2015 0.0441579781472683 2016 -0.0070494213141501 2017 -0.117812462151051 2018 -0.000688285275828093 2019 -0.000301949679851532 2020 0.00997759960591793 2021 -0.0211970582604408 2022 -0.0150013873353601