Year	Number
2000	18000
2001	17000
2002	17000
2003	17000
2004	16000
2005	16000
2006	16000
2007	16000
2008	15000
2009	15000
2010	15000
2011	15000
2012	15000
2013	14000
2014	13000
2015	13000
2016	13000
2017	13000
2018	12000
2019	12000
2020	11000