Year	Number
1996	18.0904521942139
1998	13.5
2000	9.45273590087891
2002	9.45273590087891
2003	9.95024871826172
2004	8.17307662963867
2005	11.9617223739624
2006	11.9617223739624
2007	11.9617223739624
2008	9.13461494445801
2009	14.2180099487305
2010	17.0616111755371
2011	12.6760559082031
2012	12.2065725326538
2013	13.6150236129761
2014	13.942307472229
2015	12.8571424484253
2016	11.9047622680664
2017	15.2380952835083
2018	17.619047164917
2019	18.5714282989502
2020	17.619047164917
2021	19.5238094329834
2022	18.3962268829346