Year	Number
1971	407978
1972	417523
1973	408464
1974	405203
1975	391905
1976	337575
1977	341421
1978	343759
1979	345603
1980	344524
1981	341054
1982	336605
1983	325763
1984	316740
1985	310639
1986	300748
1987	289998
1988	287490
1989	290227
1990	299984
1991	305979
1992	315866
1993	314242
1994	318747
1995	321699
1996	325661
1997	329301
1998	333053
1999	332797
2000	328649
2001	322721
2002	320560
2003	318790
2004	305970
2005	307491
2006	307997
2007	306618
2008	304729
2009	300848
2010	295322
2011	288779
2012	281315
2013	288830
2014	285273
2015	282303
2016	281334
2017	281776