Year	Number
1996	0.421715974807739
1998	0.381433337926865
2000	0.396205484867096
2002	0.392881572246552
2003	0.31808802485466
2004	0.308294892311096
2005	0.300349622964859
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	0.234690770506859
2022	0.233039766550064