Year	Number
1970	594031
1971	600367
1972	589076
1973	608581
1974	570490
1975	559033
1976	529650
1977	534708
1978	453181
1979	404569
1980	384475
1981	384787
1982	411312
1983	456480
1984	465216
1985	455343
1986	379919
1987	344482
1988	328380
1989	316976
1990	336756
1991	350005
1992	434602
1993	399160
1994	434300
1995	368511
1996	277499
1997	231918
1998	96339
1999	119295
2000	117253
2001	103413
2002	126961
2003	136943
2004	141340
2005	76430
2006	74316
2007	59098
2008	58906
2009	63903
2010	71722
2011	55679
2012	39881
2013	44537
2014	87468
2015	81001
2016	80460
2017	96064
2018	142284