Year	Number
1970	41300000
1971	42500000
1972	44900000
1973	47300000
1974	49700000
1975	52500000
1976	55100000
1977	57900000
1978	61000000
1979	64600000
1980	68600000
1981	72200000
1982	76900000
1983	82800000
1984	87400000
1985	92000000
1986	96800000
1987	100000000
1988	104000000
1989	107000000
1990	112000000
1991	119000000
1992	125000000
1993	132000000
1994	138000000
1995	143000000
1996	148000000
1997	154000000
1998	159000000
1999	162000000
2000	169000000
2001	174000000
2002	181000000
2003	189000000
2004	194000000
2005	200000000
2006	206000000
2007	214000000
2008	220000000
2009	223000000
2010	232000000
2011	241000000
2012	248000000
2013	251000000
2014	263000000
2015	266000000
2016	271000000
2017	270000000
2018	274000000