Year	Number
1996	12.5
1998	12.93532371521
2000	8.4577112197876
2002	9.95024871826172
2003	6.96517419815063
2004	7.692307472229
2005	8.17307662963867
2006	12.0192308425903
2007	10.0961542129517
2008	11.5384616851807
2009	12.3222751617432
2010	12.3222751617432
2011	12.2065725326538
2012	13.1455402374268
2013	13.1455402374268
2014	10.3448276519775
2015	9.85221672058105
2016	8.3743839263916
2017	8.86699485778809
2018	11.1650485992432
2019	12.5603866577148
2020	13.043478012085
2021	13.5265703201294
2022	14.9758453369141