Year	Number
1996	0.421715974807739
1998	0.381433337926865
2000	0.396205484867096
2002	0.392881572246552
2003	0.330509543418884
2004	0.345351129770279
2005	0.352396249771118
2006	0.355119943618774
2007	0.324082791805267
2008	0.282790422439575
2009	0.26473930478096
2010	0.260473906993866
2011	0.25491926074028
2012	0.235229834914207
2013	0.240286439657211
2014	0.210570260882378
2015	0.213650554418564
2016	0.21085649728775
2017	0.219212144613266
2018	0.217243075370789
2019	0.234910249710083
2020	0.237614139914513
2021	0.239949867129326
2022	0.239937707781792