Year	Number
2000	2000
2001	1800
2002	1700
2003	1800
2004	1600
2005	1600
2006	1500
2007	1600
2008	1800
2009	1800
2010	1800
2011	1900
2012	2600
2013	2500
2014	2500
2015	2500
2016	2800
2017	2700
2018	2700
2019	2400
2020	2700