Year	Number
1971	511929
1972	584153
1973	665088
1974	768864
1975	858924
1976	956427
1977	1053625
1978	1112554
1979	1493646
1980	1534143
1981	1617465
1982	1572587
1984	1754925
1985	1859140
1986	1870360
1987	1829559
1988	1764644
1989	1748290
1990	1779650
1991	1864465
1992	2036097
1993	2269498
1994	2548901
1995	2835331
1996	3144482
1997	3267449
1998	3358470
2001	3449077
2002	3557814
2004	3635825
2005	3847463
2006	3826601
2007	4022035
2008	3952230
2009	4002493
2010	4054280
2011	4135781
2012	4046655
2013	3925508
2014	6065280
2015	6072263
2016	5916512
2017	5684327
2018	5609433