Year	Number
1996	17.5
1998	22.3880596160889
2000	24.3781089782715
2002	28.8557205200195
2003	27.8606967926025
2004	24.519229888916
2005	29.8076915740967
2006	34.1346168518066
2007	35.5769233703613
2008	34.6153831481934
2009	36.0189590454102
2010	36.0189590454102
2011	35.6807518005371
2012	35.6807518005371
2013	35.6807518005371
2014	34.4827575683594
2015	31.5270938873291
2016	33.0049247741699
2017	32.019702911377
2018	30.5825233459473
2019	27.0531406402588
2020	22.2222213745117
2021	22.7053146362305
2022	25.1207733154297