Year	Number
1996	4.52261304855347
1998	3.5
2000	2.98507452011108
2002	18.9054718017578
2003	20.3980102539063
2004	19.230770111084
2005	15.3110046386719
2006	14.3540668487549
2007	13.3971290588379
2008	15.384614944458
2009	14.2180099487305
2010	13.7440757751465
2011	13.1455402374268
2012	14.0845069885254
2013	17.8403759002686
2014	11.057692527771
2015	8.09523773193359
2016	9.5238094329834
2017	9.5238094329834
2018	13.8095235824585
2019	11.4285717010498
2020	14.2857141494751
2021	13.3333330154419
2022	13.2075471878052