Year	Number
1996	0.421715974807739
1998	0.381433337926865
2000	0.396205484867096
2002	0.392881572246552
2003	0.330509543418884
2004	0.315975606441498
2005	0.317887514829636
2006	0.30454283952713
2007	0.324082791805267
2008	0.325011342763901
2009	0.282444268465042
2010	0.285606533288956
2011	0.29156631231308
2012	0.262924671173096
2013	0.247866421937943
2014	0.210570260882378
2015	0.213650554418564
2016	0.21855928003788
2017	0.227142184972763
2018	0.225699260830879
2019	0.240575924515724
2020	0.237614139914513
2021	0.239949867129326
2022	0.239937707781792