Year	Number
1985	4268
1986	3697
1987	4252
1988	5037
1989	5106
1990	6202
1991	7804
1992	10500
1993	12695
1994	11924
1995	10680
1996	12406
1997	13517
1998	14852
1999	16913
2000	26458
2001	31348
2002	41316
2003	58534
2004	67758
2005	95623
2006	124699
2007	155403
2008	197106
2009	232276
2010	296605
2011	418851
2012	537991
2013	709167
2014	805159
2015	972679
2016	1209288
2017	1251164