Year	Number
1996	0.421715974807739
1998	0.381433337926865
2000	0.396205484867096
2002	0.392881572246552
2003	0.330509543418884
2004	0.316001296043396
2005	0.300349622964859
2006	0.273782998323441
2007	0.262691110372543
2008	0.263591170310974
2009	0.26473930478096
2010	0.260473906993866
2011	0.25491926074028
2012	0.235229834914207
2013	0.240286439657211
2014	0.204697266221046
2015	0.205684825778008
2016	0.213261350989342
2017	0.221287682652473
2018	0.220179930329323
2019	0.23479625582695
2020	0.232469826936722
2021	0.234690770506859
2022	0.233039766550064