Year	Number of
2000	3300
2001	3200
2002	3400
2003	3600
2004	3300
2005	3300
2006	3100
2007	2700
2008	2400
2009	2000
2010	1600
2011	1600
2012	1200
2013	1100
2014	1500
2015	2400
2016	1800
2017	1900
2018	2000
2019	1900
2020	2200