Year	Number
1996	0.373912304639816
1998	0.345668405294418
2000	0.342506408691406
2002	0.316015273332596
2003	0.301584661006927
2004	0.293032377958298
2005	0.286872625350952
2006	0.257249593734741
2007	0.248241752386093
2008	0.2520891726017
2009	0.251998424530029
2010	0.249322861433029
2011	0.244249582290649
2012	0.235229834914207
2013	0.240286439657211
2014	0.204697266221046
2015	0.213650554418564
2016	0.214848384261131
2017	0.223669856786728
2018	0.221663177013397
2019	0.240575924515724
2020	0.237614139914513
2021	0.239949867129326
2022	0.239937707781792