Year	Number
1996	0.480888694524765
1998	0.453148931264877
2000	0.461006760597229
2002	0.427986711263657
2003	0.395839601755142
2004	0.393849045038223
2005	0.281408816576004
2006	0.315948367118835
2007	0.318616777658463
2008	0.327212035655975
2009	0.307390600442886
2010	0.297930240631104
2011	0.302551865577698
2012	0.297558695077896
2013	0.29543325304985
2014	0.334085315465927
2015	0.312694877386093
2016	0.314300984144211
2017	0.3108189702034
2018	0.29396253824234
2019	0.306421160697937
2020	0.304204136133194
2021	0.320136547088623
2022	0.331636041402817