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