Year	Number
1975	4266826
1976	3919111
1977	3651647
1978	3453790
1979	3311443
1980	2489186
1981	2510641
1982	2277345
1983	2439145
1984	2545995
1985	2494538
1986	2175822
1987	1812232
1988	1565763
1989	1417841
1990	1463506
1991	1382883
1992	1548773
1993	1572838
1994	1593229
1995	1474594
1996	1495065
1997	1358163
1998	1034769
1999	872268
2000	915106
2001	723338
2002	894830
2003	898306
2004	867414
2005	614276
2006	568461
2007	518364
2008	530725
2009	562997
2010	666013
2011	710248
2012	687430
2013	647831
2014	577027
2015	550642
2016	386681
2017	396518
2018	524146