Year Number 2004 0.276366174221039 2005 1.22305524349213 2006 1.15447616577148 2007 1.1724054813385 2008 1.3077244758606 2009 1.33094000816345 2010 1.2867397069931 2011 1.29547333717346 2012 1.05189907550812 2013 1.07990694046021 2014 0.489243447780609 2015 0.618334889411926 2016 0.640448570251465 2017 0.584569811820984 2018 0.560043096542358 2019 0.557111740112305 2020 0.539356708526611 2021 0.557350099086761 2022 0.578853130340576