Year	Number
1985	583
1986	977
1987	1276
1988	1722
1989	2536
1990	3738
1991	5539
1992	7809
1993	9232
1994	11912
1995	15919
1996	22428
1997	28561
1998	32575
1999	38922
2000	49236
2001	59277
2002	76937
2003	90542
2004	105379
2005	156402
2006	191772
2007	257181
2008	305497
2009	347587
2010	415229
2011	513268
2012	647999
2013	653201
2014	557689
2015	560532
2016	642406
2017	620576