Year	Number
1970	10700000
1971	10500000
1972	11100000
1973	11600000
1974	12100000
1975	12700000
1976	13500000
1977	14200000
1978	14700000
1979	16700000
1980	17200000
1981	17700000
1982	18300000
1983	18900000
1984	20600000
1985	19800000
1986	23500000
1987	24400000
1988	25100000
1989	25400000
1990	25600000
1991	25600000
1992	25600000
1993	26200000
1994	27000000
1995	28200000
1996	29300000
1997	30100000
1998	31600000
1999	31200000
2000	31300000
2001	31500000
2002	30700000
2003	30700000
2004	32600000
2005	33200000
2006	35000000
2007	36900000
2008	39100000
2009	40400000
2010	41800000
2011	42800000
2012	43100000
2013	46200000
2014	44700000
2015	43200000
2016	42500000
2017	43400000
2018	43800000