Year	Number
1970	9709540
1971	9460741
1972	9930263
1973	10500000
1974	11000000
1975	11600000
1976	12600000
1977	13400000
1978	13900000
1979	16000000
1980	16700000
1981	17300000
1982	18100000
1983	18800000
1984	20700000
1985	19800000
1986	23400000
1987	24400000
1988	25000000
1989	25100000
1990	25100000
1991	25000000
1992	25000000
1993	25400000
1994	26200000
1995	27200000
1996	28300000
1997	29200000
1998	30600000
1999	30200000
2000	30300000
2001	30600000
2002	30300000
2003	30600000
2004	33000000
2005	33900000
2006	36100000
2007	38300000
2008	40700000
2009	42200000
2010	43800000
2011	45000000
2012	45500000
2013	48600000
2014	47100000
2015	45800000
2016	45100000
2017	46000000
2018	46300000