Year	Number
1971	216775
1972	235750
1973	257308
1974	282195
1975	317799
1976	347146
1977	372100
1978	398033
1979	425870
1980	434181
1981	437956
1982	432431
1983	428117
1984	422405
1985	416203
1986	411388
1987	413466
1988	412501
1991	431381
1992	446339
1993	445785
1994	455935
1995	458199
1996	459845
1998	458118
1999	455872
2000	453465
2001	475086
2002	474861
2003	475673
2004	481049
2005	488005
2006	491901
2007	502610
2008	507357
2009	506086
2010	502659
2011	481487
2012	480642
2013	432836
2014	408799
2015	385992
2016	364243
2017	349159
2018	341591