Year	Number
1996	2.18579244613647
1998	2.7322404384613
2000	2.7322404384613
2002	3.24324321746826
2003	3.24324321746826
2004	3.48258709907532
2005	4.41176462173462
2006	9.26829242706299
2007	10.6796112060547
2008	9.70873832702637
2009	10.0478467941284
2010	7.65550231933594
2011	8.05687236785889
2012	11.8483409881592
2013	7.10900497436523
2014	7.692307472229
2015	7.14285707473755
2016	7.14285707473755
2017	8.09523773193359
2018	8.09523773193359
2019	7.61904764175415
2020	7.61904764175415
2021	8.09523773193359
2022	8.01886749267578