Year	Number
2004	0.42519822716713
2005	0.443682581186295
2006	0.423959523439407
2007	0.382787048816681
2008	0.383233666419983
2009	0.370833456516266
2010	0.39340415596962
2011	0.335981905460358
2012	0.301696002483368
2013	0.324702829122543
2014	0.259938985109329
2015	0.270398736000061
2016	0.272953003644943
2017	0.284396678209305
2018	0.261345505714417
2019	0.269838035106659
2020	0.266791701316834
2021	0.277728945016861
2022	0.284528344869614