Year	Number
1996	0.47480720281601
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	0.226807355880737
2013	0.231508240103722
2014	0.20011305809021
2015	0.204930633306503
2016	0.21085649728775
2017	0.219212144613266
2018	0.217243075370789
2019	0.234910249710083
2020	0.237614139914513
2021	0.239949867129326
2022	0.239937707781792