Year	Number
1970	3386786
1971	3413134
1972	3388772
1973	3288809
1974	3215815
1975	3218814
1976	3099422
1977	2926566
1978	2838324
1979	2505093
1980	2439896
1981	2183540
1982	2182065
1983	2211852
1984	2300880
1985	2219127
1986	2322570
1987	2326319
1988	2434530
1989	2664363
1990	2542036
1991	2472452
1992	2380064
1993	2381414
1994	2609718
1995	2684602
1996	2550188
1997	2786854
1998	1772438
1999	1300520
2000	1154603
2001	1203431
2002	1256676
2003	1262818
2004	1265386
2005	798954
2006	1081720
2007	922965
2008	695518
2009	622133
2010	726236
2011	781769
2012	767917
2013	828579
2014	910999
2015	886836
2016	883013
2017	835331
2018	1014139