Year	Number
1970	13333281
1971	13380383
1972	12991780
1973	12613432
1974	13046061
1975	12904010
1976	12781084
1977	12685905
1978	12717310
1979	12895339
1980	12917155
1981	13088844
1982	13439385
1983	13582795
1984	14376200
1985	14908755
1986	15390198
1987	16029276
1988	16024275
1989	16697284
1990	17538500
1991	17535034
1992	18099928
1993	18655600
1994	18791980
1995	18381932
1996	18646676
1997	18220364
1998	18724972
1999	19403364
2000	18585400
2001	17936310
2002	16736161
2003	15643407
2004	14905684
2005	13839449
2006	13078093
2007	12642095
2008	11447722
2009	11617466
2010	12200000
2011	11700000
2012	11800000
2013	11800000
2014	11800000
2015	12000000
2016	12100000
2017	12000000
2018	12300000