Year	Number
1996	0.613030731678009
1998	0.575733542442322
2000	0.595203697681427
2002	0.518141508102417
2003	0.412701427936554
2004	0.42519822716713
2005	0.443682581186295
2006	0.362917214632034
2007	0.331106036901474
2008	0.332146733999252
2009	0.326683729887009
2010	0.328449696302414
2011	0.340797632932663
2012	0.296924620866776
2013	0.319759637117386
2014	0.258382558822632
2015	0.261111110448837
2016	0.270750105381012
2017	0.291351109743118
2018	0.275836497545242
2019	0.31047859787941
2020	0.320069164037704
2021	0.329963147640228
2022	0.321595072746277