Year Number 2004 0.338822394609451 2005 0.357602417469025 2006 0.491848856210709 2007 0.511655807495117 2008 0.511172235012054 2009 0.500100314617157 2010 0.478729426860809 2011 0.448948442935944 2012 0.429885238409042 2013 0.457373589277267 2018 0.539004743099213 2019 0.500275909900665 2020 0.578547716140747 2021 0.548238813877106 2022 0.507792770862579