Year	Number
1971	1012920
1972	1400213
1973	1513988
1974	1653580
1975	1818323
1976	1988670
1977	2109381
1978	2202863
1981	2516592
1982	2677634
1983	2566151
1984	2685076
1985	2922576
1986	3204445
1987	3376272
1988	3640541
1989	4087736
1990	4456342
1991	4822087
1992	5311988
1993	5995051
1994	6683832
1995	7284611
1999	9140713
2000	9281424
2001	9234774
2002	9180173
2003	8885128
2004	8569090
2005	8190596
2006	7910673
2007	7457764
2008	7348681
2009	7054205
2010	6556388
2011	6435868
2012	6305168
2013	4959951
2014	4899693
2015	4880395
2016	4902204
2017	4920798