Year	Number
1970	5030126
1971	5183583
1972	5469961
1973	5731820
1974	5973857
1975	6361516
1976	6772001
1977	7163439
1978	7695815
1979	8292010
1980	9073489
1981	9979705
1982	10800000
1983	11800000
1984	12900000
1985	13500000
1986	13400000
1987	13900000
1988	14300000
1989	14300000
1990	14900000
1991	15500000
1992	15900000
1993	16400000
1994	17100000
1995	18000000
1996	18700000
1997	19200000
1998	20300000
1999	21100000
2000	22100000
2001	23900000
2002	25400000
2003	27200000
2004	29500000
2005	31200000
2006	33100000
2007	34500000
2008	37500000
2009	40300000
2010	43500000
2011	46100000
2012	48800000
2013	53300000
2014	53100000
2015	55400000
2016	56100000
2017	57800000
2018	59700000