Year Number 1996 0.264631718397141 1998 0.274148970842361 2000 0.486361712217331 2002 0.547456383705139 2003 1.12089920043945 2004 1.3520268201828 2005 1.28561401367188 2006 0.973312020301819 2007 0.456923127174377 2008 0.479434996843338 2009 0.605377018451691 2010 0.573578119277954 2011 0.607760488986969 2012 0.62878555059433 2013 0.757722914218903 2014 1.20616853237152 2015 1.18745315074921 2016 1.39056718349457 2017 1.40712821483612 2018 1.22957813739777 2019 1.2152909040451 2020 1.13746881484985 2021 1.02887463569641 2022 1.12756788730621