Year Number 1996 0.703103303909302 1998 0.673875689506531 2000 0.687808454036713 2002 0.708452701568604 2003 0.724850833415985 2004 0.72966194152832 2005 0.738931596279144 2006 0.624208450317383 2007 0.657145261764526 2008 0.610481977462769 2009 0.627860844135284 2010 0.655701696872711 2011 0.620919644832611 2012 0.644012212753296 2013 0.632543802261353 2014 0.832881629467011 2015 0.464544534683228 2016 0.489676296710968 2017 0.469570875167847 2018 0.468107908964157 2019 0.473354935646057 2020 0.500586986541748 2021 0.476212650537491 2022 0.449883759021759