Year	Number
1996	0.409431099891663
1998	0.384182929992676
2000	0.377755850553513
2002	0.337325215339661
2003	0.315908581018448
2004	0.330618888139725
2005	0.340742081403732
2006	0.317671149969101
2007	0.310351073741913
2008	0.3154336810112
2009	0.293007612228394
2010	0.282069832086563
2011	0.273884326219559
2012	0.254446119070053
2013	0.261302709579468
2014	0.218982502818108
2015	0.223781511187553
2016	0.228173807263374
2017	0.237186849117279
2018	0.234690293669701
2019	0.250075668096542
2020	0.247393816709518
2021	0.248921230435371
2022	0.248592063784599