Year Number 1996 0.17475751042366 1998 0.132018834352493 2000 0.459468245506287 2002 0.438226073980331 2003 -0.047485888004303 2004 -0.0905463024973869 2005 0.19302661716938 2006 -0.150648653507233 2007 -0.276731640100479 2008 -0.383085459470749 2009 -0.474599570035934 2010 -0.318043738603592 2011 0.0211045369505882 2012 -0.0295164491981268 2013 0.0120177594944835 2014 0.243121743202209 2015 0.24116013944149 2016 0.402214497327805 2017 0.270845115184784 2018 0.275779157876968 2019 0.292700946331024 2020 0.411397874355316 2021 0.509131908416748 2022 0.265326976776123