Year	Number
1970	9911428
1971	9667053
1972	10200000
1973	10800000
1974	11300000
1975	11900000
1976	12900000
1977	13800000
1978	14300000
1979	16500000
1980	17200000
1981	17900000
1982	18600000
1983	19500000
1984	21300000
1985	20500000
1986	24200000
1987	25200000
1988	25900000
1989	26000000
1990	26100000
1991	26000000
1992	26000000
1993	26400000
1994	27200000
1995	28400000
1996	29500000
1997	30400000
1998	31800000
1999	31400000
2000	31600000
2001	31900000
2002	31600000
2003	31900000
2004	34300000
2005	35300000
2006	37500000
2007	39700000
2008	42300000
2009	43900000
2010	45700000
2011	46900000
2012	47400000
2013	50500000
2014	49100000
2015	47800000
2016	47200000
2017	48200000
2018	48600000