Year	Number
1970	28000000
1971	34500000
1972	39900000
1973	45000000
1974	44200000
1975	46900000
1976	56100000
1977	70500000
1978	80800000
1979	79800000
1980	74200000
1981	71000000
1982	65200000
1983	63100000
1984	62300000
1985	65000000
1986	67500000
1987	70800000
1988	71900000
1989	70500000
1990	67900000
1991	68600000
1992	70400000
1993	72200000
1994	73200000
1995	77500000
1996	83100000
1997	88600000
1998	93200000
1999	97600000
2000	103000000
2001	108000000
2002	114000000
2003	121000000
2004	125000000
2005	125000000
2006	125000000
2007	125000000
2008	123000000
2009	122000000
2010	120000000
2011	119000000
2012	117000000
2013	116000000
2014	114000000
2015	115000000
2016	114000000
2017	115000000
2018	118000000