Year	Number
1996	0.47480720281601
1998	0.435220897197723
2000	0.453906059265137
2002	0.436297506093979
2003	0.349641561508179
2004	0.330648332834244
2005	0.332869827747345
2006	0.28942021727562
2007	0.280838459730148
2008	0.285063475370407
2009	0.293007612228394
2010	0.282069832086563
2011	0.273884326219559
2012	0.254446119070053
2013	0.261302709579468
2014	0.218982502818108
2015	0.223781511187553
2016	0.22340901196003
2017	0.231890723109245
2018	0.229462996125221
2019	0.243729904294014
2020	0.247393816709518
2021	0.248921230435371
2022	0.248592063784599