Year	Number
1971	476436
1972	531550
1974	332741
1975	363629
1976	432958
1977	458033
1978	478830
1979	496558
1980	555100
1981	699662
1982	819549
1983	899040
1984	911692
1985	850920
1986	831533
1987	880743
1988	872718
1989	867644
1990	849649
1991	792481
1992	818202
1993	812768
1994	797507
1995	835049
1996	851390
1997	882560
1998	1154412
1999	1238452
2000	1367199
2001	1413243
2002	1448550
2003	1592014
2004	1539602
2005	1484187
2006	1601862
2007	1675606
2008	1855497
2009	1763509
2010	1870448
2011	1885464
2012	2019131
2013	3425040
2014	3519745
2015	3667719
2016	3784089
2017	3754609