Year	Number
1996	19.5
1998	23.3830852508545
2000	21.3930339813232
2002	17.412935256958
2003	11.4427862167358
2004	12.9807691574097
2005	10.5769233703613
2006	8.17307662963867
2007	7.692307472229
2008	7.21153831481934
2009	6.63507127761841
2010	6.63507127761841
2011	7.0422534942627
2012	5.63380289077759
2013	5.16431903839111
2014	5.9113302230835
2015	7.88177347183228
2016	12.3152713775635
2017	12.8078813552856
2018	12.62135887146
2019	12.0772943496704
2020	8.21256065368652
2021	9.17874431610107
2022	8.69565200805664