Year	Number
1971	421270
1972	451917
1973	359069
1974	385642
1975	456816
1976	550068
1977	616916
1978	647229
1979	790626
1980	858993
1981	888721
1982	947078
1983	1051835
1984	945198
1985	969488
1986	1206330
1987	1243953
1988	1297108
1989	1234045
1990	1037984
1991	1101770
1992	1155023
1993	1227137
1994	1228109
1995	1186977
1996	1144286
1997	905911
1998	507571
1999	444318
2000	409189
2001	432196
2002	443665
2003	410301
2004	422790
2005	487314
2006	482220
2007	492411
2008	494411
2009	482102
2010	532582
2011	566815
2012	583036
2013	547099
2014	572184
2015	609543
2016	614147
2017	621174