Year	Number
1970	12400000
1971	12900000
1972	13500000
1973	14200000
1974	14600000
1975	15300000
1976	15900000
1977	16500000
1978	17300000
1979	18100000
1980	19500000
1981	20100000
1982	21400000
1983	23000000
1984	24600000
1985	25600000
1986	25700000
1987	26700000
1988	27400000
1989	27900000
1990	28500000
1991	30600000
1992	32400000
1993	33500000
1994	35000000
1995	37000000
1996	38500000
1997	39900000
1998	42200000
1999	44100000
2000	46400000
2001	49300000
2002	52000000
2003	55300000
2004	58300000
2005	60500000
2006	64300000
2007	66800000
2008	70300000
2009	74300000
2010	78700000
2011	82200000
2012	86100000
2013	91100000
2014	91300000
2015	94900000
2016	97500000
2017	99100000
2018	102000000