Year	Number
1970	120200
1971	125500
1972	122800
1973	130300
1974	136200
1975	139700
1976	190400
1977	176700
1978	170000
1979	175000
1980	331100
1981	340000
1982	421000
1983	428300
1984	436100
1985	456000
1986	459500
1987	393100
1988	382800
1989	406700
1990	398300
1991	436000
1992	471400
1993	302300
1994	505200
1995	508200
1996	431300
1997	468500
1998	466700
1999	423100
2000	446688
2001	373904
2002	365877
2003	385529
2004	430873
2005	465343
2006	508368
2007	535324
2008	545640
2009	524867
2010	243635.528989967
2011	121233.395658112
2012	42729.3194712764
2013	0
2015	137331
2016	77320