Year	Number
1996	7.60869550704956
1998	9.78260898590088
2000	15.2173910140991
2002	16.2162170410156
2003	20.5405406951904
2004	19.9004974365234
2005	20.5882358551025
2006	22.5490188598633
2007	22.3300971984863
2008	22.3300971984863
2009	25.8373203277588
2010	23.4449768066406
2011	28.4360198974609
2012	30.3317527770996
2013	25.5924167633057
2014	24.519229888916
2015	20
2016	18.5714282989502
2017	20
2018	13.8095235824585
2019	12.8571424484253
2020	11.9047622680664
2021	10.9523811340332
2022	15.5660381317139