Year	Number
1971	342336
1972	327801
1973	321250
1974	295309
1975	282469
1976	272242
1977	265576
1978	262613
1979	262540
1980	264062
1981	267934
1982	282484
1983	298388
1984	308355
1985	315570
1986	316529
1987	316683
1988	320956
1989	337181
1990	370891
1991	390649
1992	400673
1994	450733
1995	446199
1996	409508
1997	405281
1998	43995
1999	55044
2000	50821
2001	57772
2002	65400
2003	67269
2004	130498
2005	130983
2006	129434
2007	127829
2008	130557
2009	131455
2010	137774
2011	139332
2012	139127
2013	133788
2014	120526
2015	105768
2016	93917
2017	98381