Year	Number
2000	2700
2001	2500
2002	2500
2003	2300
2004	2200
2005	2100
2006	2000
2007	1900
2008	1800
2009	1800
2010	1700
2011	1600
2012	1600
2013	1500
2014	1400
2015	1400
2016	1400
2017	1300
2018	1300
2019	1200
2020	1300