Year	Number
2000	11000
2001	12000
2002	13000
2003	14000
2004	15000
2005	15000
2006	16000
2007	16000
2008	16000
2009	16000
2010	17000
2011	17000
2012	17000
2013	18000
2014	18000
2015	18000
2016	19000
2017	19000
2018	20000
2019	20000
2020	21000