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