Year	Number
1970	291133
1971	303502
1972	301269
1973	295055
1974	281650
1975	263385
1976	252486
1977	250202
1978	262491
1979	268573
1980	266834
1981	260530
1982	254400
1983	257516
1984	254518
1985	250210
1986	263809
1987	273675
1988	287019
1989	305658
1990	331645
1991	341116
1992	357806
1993	364702
1994	354743
1995	363917
1996	360763
1997	361857
1998	360194
1999	363622
2000	324796
2001	303928
2002	292916
2003	281893
2004	279714
2005	270815
2006	254362
2007	250471
2008	247546
2009	243290
2010	233291
2011	223419
2012	218560
2013	221183
2014	221076
2015	219136
2016	218597
2017	210417
2018	219567