Year	Number
1970	485058.1
1971	495131.2
1972	546149.1
1973	590751.9
1974	690591.3
1975	732053.1
1976	812178.1
1977	935050.4
1978	1017524
1979	1101284
1980	1162387
1981	1250134
1982	1348664
1983	1417950
1984	1465057
1985	1548736
1986	1735064
1987	1858323
1988	1914454
1989	1962175
1990	1972829
1991	2032448
1992	2043428
1993	2431210
1994	2779333
1995	2806957
1996	2895991
1997	3150560
1998	3415374
1999	3622017
2000	3856347
2001	4049321
2002	4125743
2003	4289053
2004	4479446
2005	4256246
2006	4037603
2007	3647440
2008	3503531
2009	3267658
2010	3266139
2011	3545361
2012	3656651
2013	3747960
2014	3601078
2015	3608390
2016	3688642
2017	3762894
2018	3864099