Year	Number
1970	105090
1998	100212
2000	36762
2001	36713
2002	29994
2003	29524
2005	17569
2006	17353
2007	20531
2008	19848
2009	18943
2010	16664
2011	16689
2012	19502
2013	30671
2014	39917
2015	49144
2016	54322