Year	Number
1996	0.373912304639816
1998	0.345668405294418
2000	0.342506408691406
2002	0.316015273332596
2003	0.301584661006927
2004	0.293032377958298
2005	0.278116136789322
2006	0.264850795269012
2007	0.262691110372543
2008	0.263591170310974
2009	0.241539120674133
2010	0.239330947399139
2011	0.246941670775414
2012	0.224335819482803
2013	0.229172840714455
2014	0.195739418268204
2015	0.199955016374588
2016	0.207869693636894
2017	0.214783161878586
2018	0.212974011898041
2019	0.228971391916275
2020	0.231230169534683
2021	0.234723269939423
2022	0.232942596077919