Year	Number
1996	0.373912304639816
1998	0.345668405294418
2000	0.342506408691406
2002	0.316015273332596
2003	0.301584661006927
2004	0.315975606441498
2005	0.286872625350952
2006	0.27938786149025
2007	0.267617672681808
2008	0.271060198545456
2009	0.251998424530029
2010	0.249322861433029
2011	0.24933560192585
2012	0.233037114143372
2013	0.238264307379723
2014	0.205589711666107
2015	0.208575189113617
2016	0.214360997080803
2017	0.222477972507477
2018	0.2210383862257
2019	0.234910249710083
2020	0.237614139914513
2021	0.234690770506859
2022	0.233039766550064