Year	Number
1996	6
1998	9.45273590087891
2000	8.95522403717041
2002	12.93532371521
2003	10.945273399353
2004	11.5384616851807
2005	12.0192308425903
2006	11.5384616851807
2007	14.4230766296387
2008	15.865385055542
2009	14.6919431686401
2010	14.6919431686401
2011	14.5539903640747
2012	15.962441444397
2013	15.962441444397
2014	15.2709360122681
2015	15.2709360122681
2016	16.7487678527832
2017	18.2266006469727
2018	22.8155345916748
2019	25.1207733154297
2020	25.6038646697998
2021	24.1545886993408
2022	26.57004737854