Year	Number
1996	0.480888694524765
1998	0.453148931264877
2000	0.461006760597229
2002	0.427986711263657
2003	0.395839601755142
2004	0.393849045038223
2005	0.340958386659622
2006	0.418964713811874
2007	0.415193498134613
2008	0.4012451171875
2009	0.292359530925751
2010	0.292717128992081
2011	0.296300768852234
2012	0.313169628381729
2013	0.309244394302368
2014	0.305000483989716
2015	0.289382845163345
2016	0.305349111557007
2017	0.280709505081177
2018	0.281422942876816
2019	0.284793734550476
2020	0.26276308298111
2021	0.30851623415947
2022	0.31724950671196