Year	Number
1971	34620
1972	35847
1973	39439
1974	42928
1975	49034
1976	55444
1977	61999
1978	70709
1979	78086
1980	78707
1981	64124
1982	75819
1983	70453
1984	73218
1985	67841
1987	63768
1988	66431
1989	75213
1990	76501
1991	84220
1992	98737
1993	102781
1994	120912
1995	139777
1996	151554
1997	168898
1998	188109
1999	217700
2000	257833
2003	349615
2004	388418
2005	429716
2006	474976
2007	533849
2008	612012
2009	686071
2010	758285
2011	821160
2013	882380
2014	961046
2015	945484
2016	1013780
2017	1017415
2018	1046493
2020	1033395