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