Year	Number
1970	104000000
1971	113000000
1972	122000000
1973	130000000
1974	133000000
1975	139000000
1976	151000000
1977	168000000
1978	181000000
1979	193000000
1980	191000000
1981	192000000
1982	190000000
1983	194000000
1984	198000000
1985	196000000
1986	213000000
1987	219000000
1988	224000000
1989	226000000
1990	231000000
1991	238000000
1992	248000000
1993	257000000
1994	264000000
1995	274000000
1996	286000000
1997	298000000
1998	307000000
1999	316000000
2000	330000000
2001	341000000
2002	355000000
2003	367000000
2004	376000000
2005	381000000
2006	386000000
2007	392000000
2008	398000000
2009	401000000
2010	410000000
2011	418000000
2012	425000000
2013	431000000
2014	440000000
2015	444000000
2016	449000000
2017	449000000
2018	456000000