Year	Number
1970	27437
1971	14665
1972	15192
1973	16473
1974	19149
1975	22172
1976	26630
1977	32229
1978	41608
1979	48671
1980	48750
1981	43841
1982	52631
1983	57098
1984	58297
1987	68595
1988	69841
1989	66708
1991	67954
1992	77061
1993	88588
1998	96813
2000	87280
2001	86226
2002	100322
2003	102974
2004	110660
2005	107863
2006	106908
2007	104165
2008	104281
2009	105755
2010	105413
2011	92868
2012	113270
2013	114532
2014	112268
2015	107652
2016	100848
2017	94437
2018	91653