Year	Number of
2000	4400
2001	4100
2002	3500
2003	3500
2004	2900
2005	2600
2006	3200
2007	3100
2008	2300
2009	2200
2010	2600
2011	2400
2012	1800
2013	1500
2014	1600
2015	1900
2016	1300
2017	1000
2018	1200
2019	1800
2020	2300