Year	Number
1971	186261
1972	239032
1973	278843
1974	302519
1975	406565
1976	487648
1977	589227
1978	718122
1979	821168
1980	906938
1981	1000486
1982	1124100
1983	1260862
1984	1420303
1985	1569167
1986	1756506
1987	1877553
1988	1954563
1989	1954869
1990	1997287
1991	2022220
1992	2136755
1993	2176076
1994	2290904
1995	2336114
1996	2397446
1997	2480168
1999	2745950
2000	2732268
2001	2906695
2002	3071700
2003	3192247
2004	3254812
2005	3291971
2006	3315701
2007	3417684
2008	3542924
2009	4139007
2010	4227264
2011	4191623
2012	4202919
2013	4165480
2014	4132124
2015	4131265
2016	4016153
2017	4007721
2018	4075023