Year	Number
1996	0.409431099891663
1998	0.345668405294418
2000	0.342506408691406
2002	0.316015273332596
2003	0.301584661006927
2004	0.293032377958298
2005	0.278116136789322
2006	0.273782998323441
2007	0.262691110372543
2008	0.263591170310974
2009	0.246055126190186
2010	0.243547096848488
2011	0.244249582290649
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