Year	Number
2000	18000
2001	20000
2002	22000
2003	23000
2004	24000
2005	24000
2006	24000
2007	23000
2008	22000
2009	20000
2010	19000
2011	18000
2012	17000
2013	16000
2014	15000
2015	15000
2016	14000
2017	14000
2018	13000
2019	12000
2020	12000