Year	Number
1996	0.421715974807739
1998	0.381433337926865
2000	0.396205484867096
2002	0.392881572246552
2003	0.330509543418884
2004	0.316001296043396
2005	0.311466783285141
2006	0.316885411739349
2007	0.290890961885452
2008	0.292073458433151
2009	0.272184789180756
2010	0.267576217651367
2011	0.260717630386353
2012	0.242201656103134
2013	0.247866421937943
2014	0.210570260882378
2015	0.209370508790016
2016	0.213261350989342
2017	0.221287682652473
2018	0.220179930329323
2019	0.23479625582695
2020	0.232469826936722
2021	0.234690770506859
2022	0.233039766550064