Year	Number
1996	20
1998	16.9154224395752
2000	16.9154224395752
2002	16.9154224395752
2003	19.9004974365234
2004	19.7115383148193
2005	17.7884616851807
2006	19.230770111084
2007	19.230770111084
2008	18.269229888916
2009	17.0616111755371
2010	17.0616111755371
2011	19.2488269805908
2012	17.3708915710449
2013	17.8403759002686
2014	21.674877166748
2015	22.660099029541
2016	21.1822662353516
2017	20.1970443725586
2018	17.4757289886475
2019	15.9420289993286
2020	15.4589376449585
2021	17.8743953704834
2022	17.3913040161133