Year	Number
2000	15000
2001	15000
2002	15000
2003	16000
2004	16000
2005	16000
2006	16000
2007	17000
2008	17000
2009	17000
2010	18000
2011	18000
2012	19000
2013	19000
2014	19000
2015	20000
2016	20000
2017	21000
2018	20000
2019	21000
2020	22000