Year	Number
1970	10700000
1971	10800000
1972	11100000
1973	11400000
1974	11600000
1975	11700000
1976	12200000
1977	12400000
1978	12800000
1979	13000000
1980	13100000
1981	13100000
1982	13500000
1983	13800000
1984	13700000
1985	13800000
1986	14200000
1987	14200000
1988	14200000
1989	13900000
1990	13800000
1991	13800000
1992	13700000
1993	14300000
1994	15000000
1995	14900000
1996	14800000
1997	14200000
1998	11700000
1999	12000000
2000	10900000
2001	11100000
2002	10900000
2003	10700000
2004	12000000
2005	12200000
2006	11300000
2007	11200000
2008	11000000
2009	10700000
2010	10800000
2011	10400000
2012	10200000
2013	11600000
2014	11300000
2015	11000000
2016	11000000
2017	11100000
2018	11200000