Year	Number
1971	1107906
1972	1225468
1974	1957109
1975	2190412
1976	2506014
1977	2805474
1978	3024000
1979	3417693
1980	3729916
1981	4042188
1982	4512582
1983	4817198
1984	5152572
1985	5396936
1986	5717572
1987	5821989
1988	5933355
1989	5998119
1990	5945595
1991	5911816
1992	5885986
1993	5970118
1994	6179579
1995	6429571
1996	6738024
1997	7031605
1998	7252370
1999	7483274
2000	7726904
2001	7943901
2002	8244426
2003	8596171
2004	8864251
2005	9080217
2006	9281593
2007	9446670
2008	9588558
2009	9711334
2010	9811082
2011	9950960
2012	10120115
2013	9042238
2014	9473577
2015	9805487
2016	9941378
2017	10279943