Year	Number
2000	1400
2001	1300
2002	1400
2003	1300
2004	1200
2005	1300
2006	1100
2007	1200
2008	1200
2009	1400
2010	1600
2011	1500
2012	1400
2013	1400
2014	1300
2015	1200
2016	1400
2017	1100
2018	1100
2019	1300
2020	1300