Year	Number
1996	0.409431099891663
1998	0.384182929992676
2000	0.377755850553513
2002	0.337325215339661
2003	0.315908581018448
2004	0.304597765207291
2005	0.29303577542305
2006	0.260218590497971
2007	0.25422665476799
2008	0.25637811422348
2009	0.261115193367004
2010	0.254323482513428
2011	0.250919014215469
2012	0.231296643614769
2013	0.238348826766014
2014	0.2031569480896
2015	0.209529757499695
2016	0.214088663458824
2017	0.222265064716339
2018	0.219739928841591
2019	0.237725615501404
2020	0.24160347878933
2021	0.24306446313858
2022	0.240944445133209