Year	Number
2004	0.393849045038223
2005	0.317097127437592
2006	0.391186147928238
2007	0.387364894151688
2008	0.386440932750702
2009	0.406062066555023
2010	0.412372380495071
2011	0.405694514513016
2012	0.32276239991188
2013	0.31312769651413
2014	0.334085315465927
2015	0.312694877386093
2016	0.314300984144211
2017	0.3108189702034
2018	0.29396253824234
2019	0.306421160697937
2020	0.304204136133194
2021	0.325693815946579
2022	0.338337033987045