Year	Number
1970	583773.3
1971	585146.8
1972	643416.2
1973	690886.6
1974	791370.8
1975	832324.2
1976	914051.8
1977	1038257
1978	1122230
1979	1208392
1980	1275580
1981	1370128
1982	1477382
1983	1554404
1984	1609748
1985	1703720
1986	1898665
1987	2029094
1988	2090557
1989	2142000
1990	2157812
1991	2223678
1992	2244470
1993	2636419
1994	2989246
1995	3020364
1996	3116722
1997	3378987
1998	3659082
1999	3862355
2000	4072789
2001	4269250
2002	4364151
2003	4534972
2004	4731572
2005	4503647
2006	4274745
2007	3879705
2008	3754193
2009	3538414
2010	3554852
2011	3850314
2012	3983020
2013	4095247
2014	3962266
2015	3969979
2016	4052828
2017	4129323
2018	4235568