Year	Number
1970	3350998
1971	3374492
1972	3341512
1973	3245684
1974	3176706
1975	3203734
1976	3098667
1977	2925920
1978	2837689
1979	2488606
1980	2405054
1981	2130668
1982	2115937
1983	2146206
1984	2232041
1985	2142799
1986	2252282
1987	2267057
1988	2375907
1989	2608042
1990	2486120
1991	2414163
1992	2332175
1993	2337164
1994	2576309
1995	2650787
1996	2524102
1997	2763100
1998	1749309
1999	1280477
2000	1134500
2001	1183993
2002	1238838
2003	1239160
2004	1239905
2005	770935
2006	1051026
2007	893491
2008	666119
2009	599313
2010	706669
2011	757693
2012	742187
2013	799496
2014	872208
2015	841840
2016	832826
2017	789279
2018	977006