Year	Number
1970	12824148
1971	12865475
1972	12465231
1973	12085497
1974	12476858
1975	12304788
1976	12186404
1977	12074768
1978	12085780
1979	12260828
1980	12269122
1981	12485034
1982	12868056
1983	12987976
1984	13754695
1985	14313527
1986	14728392
1987	15378826
1988	15343564
1989	16017157
1990	16830856
1991	16904520
1992	17481348
1993	18007868
1994	18150448
1995	17693998
1996	17927732
1997	17515812
1998	17991092
1999	18644526
2000	17897252
2001	17188644
2002	16051926
2003	14793301
2004	14033242
2005	12924416
2006	12124758
2007	11781424
2008	10643572
2009	10798013
2010	11400000
2011	11100000
2012	11200000
2013	10900000
2014	10800000
2015	11200000
2016	11400000
2017	11600000
2018	11900000