Year	Number
1980	237551
1981	190492
1982	185285
1983	211447
1984	206439
1985	200338
1986	193553
1987	197009
1988	214962
1989	219341
1990	211890
1991	200845
1992	207210
1993	197409
1994	213118
1995	248016
1996	261017
1997	288500
1998	285214
1999	315734
2000	332766
2001	372902
2002	368873
2003	359807
2004	375766
2005	402372
2006	428404
2007	445264
2008	449741
2009	425222
2010	444513
2011	456911
2012	482732
2013	499617
2014	516070
2015	530244
2016	534013
2017	539033