Year	Number
2000	1500
2001	1500
2002	1400
2003	1200
2004	1300
2005	1200
2006	1200
2007	1100
2008	1100
2009	1100
2010	1200
2011	1100
2012	1000
2013	1000
2014	1000
2015	1100
2016	1100
2017	1100
2018	1000
2019	1000
2020	890