Year	Number
2000	23000
2001	24000
2002	24000
2003	25000
2004	25000
2005	25000
2006	25000
2007	24000
2008	24000
2009	23000
2010	23000
2011	22000
2012	22000
2013	21000
2014	21000
2015	21000
2016	20000
2017	20000
2018	20000
2019	19000
2020	19000