Year	Number
1985	16496
1986	16425
1987	18163
1988	20297
1989	19537
1990	16365
1991	16557
1992	58309
1993	53321
1994	43745
1995	39260
1996	40873
1997	38934
1998	41336
1999	46618
2000	60167
2001	67296
2002	76617
2003	94829
2004	102800
2005	136704
2006	170365
2007	202233
2008	237555
2009	278684
2010	346643
2011	467015
2012	587935
2013	752247
2014	842429
2015	1015135
2016	1249178
2017	1285812