Year	Number
1996	31.7204303741455
1998	36.8983955383301
2000	32.4468078613281
2002	33.862434387207
2003	29.6296291351318
2004	31.0344829559326
2005	29.7560977935791
2006	30.2439022064209
2007	30.0970878601074
2008	41.262134552002
2009	32.0574150085449
2010	30.4761905670166
2011	30.3317527770996
2012	31.2796211242676
2013	32.2274894714355
2014	31.25
2015	28.5714282989502
2016	22.380952835083
2017	20.9523811340332
2018	21.9047622680664
2019	20
2020	22.380952835083
2021	20.9523811340332
2022	20.2830181121826