Year	Number
1996	0.47480720281601
1998	0.435220897197723
2000	0.453906059265137
2002	0.436297506093979
2003	0.349641561508179
2004	0.330648332834244
2005	0.332869827747345
2006	0.331756144762039
2007	0.308105289936066
2008	0.309818059206009
2009	0.323601871728897
2010	0.320087254047394
2011	0.306695103645325
2012	0.282746523618698
2013	0.297252923250198
2014	0.238057717680931
2015	0.249322980642319
2016	0.253411799669266
2017	0.263454109430313
2018	0.257120162248611
2019	0.280839860439301
2020	0.27869239449501
2021	0.251843899488449
2022	0.260167717933655