Year	Number
1985	17457
1986	17480
1987	19641
1988	20709
1989	21586
1990	16645
1991	17769
1992	59755
1993	66474
1994	52372
1995	47167
1996	48481
1997	46707
1998	49872
1999	55967
2000	70640
2001	79629
2002	83782
2003	103727
2004	115420
2005	152471
2006	188413
2007	226323
2008	266355
2009	304678
2010	374357
2011	495626
2012	615805
2013	783265
2014	876571
2015	1037140
2016	1288051
2017	1329624