Year	Number
1970	4205081
1971	4478712
1972	4677151
1973	4889252
1974	4990123
1975	5186123
1976	5392140
1977	5713482
1978	6167935
1979	6720441
1980	7263833
1981	7578663
1982	7881666
1983	8243868
1984	8623438
1985	8762969
1986	8858224
1987	8918607
1988	9054573
1989	9075155
1990	9078075
1991	9266755
1992	9339539
1993	9482651
1994	9861799
1995	10500000
1996	11000000
1997	11200000
1998	12300000
1999	12900000
2000	13700000
2001	14900000
2002	16200000
2003	18100000
2004	19700000
2005	21200000
2006	23100000
2007	24400000
2008	26500000
2009	28100000
2010	30100000
2011	32000000
2012	33600000
2013	34100000
2014	34700000
2015	35400000
2016	36300000
2017	37300000
2018	38300000