Year	Number
2000	2400
2001	2300
2002	2300
2003	2200
2004	2100
2005	2000
2006	1900
2007	1900
2008	1900
2009	1900
2010	1800
2011	1700
2012	1700
2013	1600
2014	1600
2015	1700
2016	1600
2017	1600
2018	1600
2019	1600
2020	1700