Year	Number
1996	15.5
1998	17.9104480743408
2000	21.8905467987061
2002	20.3980102539063
2003	20.3980102539063
2004	18.75
2005	15.384614944458
2006	10.5769233703613
2007	12.0192308425903
2008	11.057692527771
2009	13.2701425552368
2010	12.7962083816528
2011	12.6760559082031
2012	12.2065725326538
2013	9.38967132568359
2014	7.38916254043579
2015	6.89655160903931
2016	6.40394067764282
2017	6.89655160903931
2018	7.28155326843262
2019	7.24637699127197
2020	5.79710149765015
2021	7.72946882247925
2022	9.66183567047119