Year	Number
1996	0.5
1998	2.48756217956543
2000	1.99004971981049
2002	7.96019887924194
2003	6.96517419815063
2004	6.73076915740967
2005	8.17307662963867
2006	8.17307662963867
2007	8.65384578704834
2008	12.0192308425903
2009	10.4265403747559
2010	12.7962083816528
2011	12.2065725326538
2012	14.0845069885254
2013	12.6760559082031
2014	9.35960578918457
2015	9.85221672058105
2016	11.822660446167
2017	12.8078813552856
2018	17.9611644744873
2019	21.2560386657715
2020	20.7729473114014
2021	20.2898559570313
2022	21.7391300201416