Year	Number
2000	2400
2001	2300
2002	2400
2003	2200
2004	2300
2005	2300
2006	2300
2007	2200
2008	2200
2009	2100
2010	1900
2011	1900
2012	1700
2013	1800
2014	1900
2015	1900
2016	1800
2017	1800
2018	1800
2019	1800
2020	2000