Year	Number
1996	0.373912304639816
1998	0.345668405294418
2000	0.342506408691406
2002	0.316015273332596
2003	0.29205846786499
2004	0.286855816841125
2005	0.286872625350952
2006	0.273782998323441
2007	0.267617672681808
2008	0.271060198545456
2009	0.251998424530029
2010	0.243547096848488
2011	0.244249582290649
2012	0.233037114143372
2013	0.231508240103722
2014	0.20011305809021
2015	0.208575189113617
2016	0.214360997080803
2017	0.212915167212486
2018	0.213976681232452
2019	0.217577815055847
2020	0.217306077480316
2021	0.216229736804962
2022	0.222371086478233