Year	Number
1971	15426000
1972	15423000
1973	15258000
1974	15075000
1975	14669000
1976	14176000
1977	13520000
1978	12823000
1979	12098000
1980	11578000
1981	11351000
1982	11199000
1983	11242000
1984	11344000
1985	11503000
1986	11675000
1987	11851000
1988	11989000
1989	12113000
1990	12257000
1991	12363000
1992	12313000
1993	12306000
1994	12424000
1995	12829000
1996	13194000
1997	13537000
1998	13946000
1999	14186837
2000	14138837
2001	13857896
2002	13369909
2003	12536543
2004	11526311
2005	10409673
2006	9590695
2007	8956312
2008	8415648
2009	8056790
2011	7651800
2012	7589670
2013	7544082
2014	7577881
2015	7866270
2016	8051287
2017	8473262