Year	Number
1996	13.0653266906738
1998	15
2000	14.4278602600098
2002	18.9054718017578
2003	22.3880596160889
2004	19.7115383148193
2005	26.7942581176758
2006	21.5311012268066
2007	21.5311012268066
2008	22.115385055542
2009	20.3791465759277
2010	21.3270149230957
2011	17.8403759002686
2012	21.5962448120117
2013	26.2910804748535
2014	28.365385055542
2015	28.0952377319336
2016	31.9047622680664
2017	31.4285717010498
2018	28.5714282989502
2019	28.0952377319336
2020	24.2857151031494
2021	30
2022	25.943395614624