Year	Number
2004	0.410197407007217
2005	0.30711555480957
2006	0.435252577066422
2007	0.469166576862335
2008	0.451515167951584
2009	0.423608183860779
2010	0.449280053377151
2011	0.434491038322449
2012	0.398956000804901
2013	0.38144639134407
2014	0.46657195687294
2015	0.448273360729218
2016	0.43443551659584
2017	0.445859044790268
2018	0.456688791513443
2019	0.461858510971069
2020	0.492229521274567
2021	0.484019696712494
2022	0.47904047369957