Year	number
2006	12070
2007	11599
2008	9661
2009	8183
2010	9212
2011	13141
2012	13524
2013	14242
2014	13867
2015	15005
2016	16572
2017	18461
2018	19950
2019	20899
2020	20329
2021	24728
2022	20608