Year	Number
1971	2625667
1972	2771493
1973	2932114
1974	3069391
1975	3162331
1976	3343085
1977	3445104
1978	3515850
1979	3515308
1980	3499978
1981	3484339
1982	3452509
1983	3446449
1984	3413687
1985	3395935
1986	3381434
1987	3350503
1988	3290149
1989	3196146
1990	3117005
1991	2994957
1992	2900114
1993	2805158
1994	2788666
1995	2744266
1996	2696097
1997	2642456
1998	2781094
1999	2781659
2000	3768263
2001	3785269
2002	3795458
2003	3829583
2004	2810050
2005	2837999
2006	2856012
2007	2865744
2008	2884641
2009	2913355
2010	2917647
2011	2924902
2012	2925752
2013	2941755
2014	3023900
2015	3025324
2016	3015887
2017	3035462