Year	Number
1975	14482391
1976	14610455
1977	14423514
1978	14260844
1979	13860132
1980	13576540
1981	13342929
1982	13354762
1983	13614736
1984	14247419
1985	15042097
1986	16055322
1987	16997982
1988	17876272
1989	18054896
1990	18866348
1991	19038472
1992	19667740
1993	20032702
1994	20373596
1995	20138788
1996	21008736
1997	20213964
1998	20415356
1999	20667644
2000	19745684
2001	19021242
2002	18342970
2003	17410848
2004	16918796
2005	16007462
2006	15396689
2007	13757874
2008	13692379
2009	13840803
2010	14900000
2011	14200000
2012	14400000
2013	14300000
2014	14500000
2015	14800000
2016	15100000
2017	15200000
2018	15400000