Year	Number
2004	23500
2005	23900
2006	25700
2007	26000
2008	25200
2009	24000
2010	25000
2011	25500
2012	27400
2013	25100
2014	28100
2015	35300
2016	35900
2017	37900
2018	38900
2019	41000
2020	41800