Year	Number
1971	154575
1972	161796
1973	169176
1974	178557
1975	247609
1976	260999
1977	270106
1978	274188
1979	277929
1980	281904
1981	286619
1982	294973
1983	301956
1984	308411
1985	312417
1986	315584
1987	318954
1988	319122
1989	318694
1990	318601
1991	321477
1992	327817
1993	336826
1994	346742
1995	352817
1996	352820
1997	353270
1998	354252
1999	346315
2000	338247
2001	328424
2002	323043
2003	320620
2004	270724
2005	266835
2006	263224
2007	264708
2008	265746
2009	270429
2010	273481
2011	278192
2012	285692
2014	348116
2015	354670
2016	360088
2017	373014