Year	Number of
2000	4000
2001	4000
2002	3700
2003	3700
2004	3000
2005	3100
2006	2900
2007	2700
2008	2900
2009	2700
2010	2900
2011	3000
2012	2900
2013	3000
2014	2700
2015	2900
2016	3000
2017	3000
2018	2800
2019	3000
2020	3800