Year	Number
1970	44238632
1971	45031120
1972	44462856
1973	42245948
1974	42055992
1975	41479380
1976	41082048
1977	40948476
1978	42650248
1979	42125592
1980	41135372
1981	39846064
1982	39571096
1983	39281120
1984	39332632
1985	38883460
1986	38442212
1987	38750624
1988	37873740
1989	37199924
1990	38903100
1991	38784584
1992	39951892
1993	40897556
1994	42106504
1995	44022912
1996	46176300
1997	47240708
1998	45646840
1999	43343064
2000	41056196
2001	39576008
2002	38276384
2003	36153584
2004	33754360
2005	31328816
2006	31215688
2007	26917480
2008	27046428
2009	28158704
2010	28900000
2011	29300000
2012	27800000
2013	27100000
2014	26500000
2015	26800000
2016	26400000
2017	26400000
2018	26200000